newbie question about data I/O

S

Seeker

Howdy, gurus

I want to write code to read in a large genomic file. The data look
like

Marker location freq T mu sigma_2 S p-
value
rs2977670 713754 0.925 779 9.604 141.278 2.202 0.02763
rs2977656 719811 0.992 793 9.120 134.796 2.733 0.00627

Here is my code:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

int main(int argc, char** argv)
{
vector<string> snp_list1,snp_list2,snp_list3;
vector<int> location1,location2,location3;
vector<double> freq1,freq2,freq3;
vector<int> T1,T2,T3;
vector<double> mu1,mu2,mu3;
vector<double> sigma_21,sigma_22,sigma_23;
vector<double> S1,S2,S3;
vector<double> p1,p2,p3;

//read in 1st data file;
FILE *in=fopen(argv[1],"r");
char line[128];
fgets(line,128,in); //skip the 1st row;

while (fgets(line,128,in))
{

cout << line << endl;

char *str = strtok(line, "\t"); // the space in "\t" is a tab
string marker(str);
snp_list1.push_back(marker);

str = strtok(NULL, "\t");
location1.push_back(atof(str));

str = strtok(NULL, "\t");
freq1.push_back(atof(str));

str = strtok(NULL, "\t");
T1.push_back(atof(str));

str = strtok(NULL, "\t");
mu1.push_back(atof(str));

str = strtok(NULL, "\t");
sigma_21.push_back(atof(str));

str = strtok(NULL, "\t");
S1.push_back(atof(str));

str = strtok(NULL, "\t");
p1.push_back(atof(str));

}
fclose(in);

//verify the vectors
for (int i=0; i<snp_list1.size();++i)
cout << snp_list1 << endl;
return 0;
}

I tried to run the code but always met errors shown as "error while
dumping state..(core dumped)". I am new to C++.Thanks a lot for your
input.
 
F

Francesco S. Carta

Howdy, gurus

I want to write code to read in a large genomic file. The data look
like

Marker          location   freq       T      mu     sigma_2  S       p-
value
rs2977670     713754   0.925     779   9.604 141.278   2.202  0.02763
rs2977656     719811   0.992     793   9.120 134.796   2.733  0.00627

Here is my code:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

int main(int argc, char** argv)
{
        vector<string> snp_list1,snp_list2,snp_list3;
        vector<int>    location1,location2,location3;
        vector<double> freq1,freq2,freq3;
        vector<int> T1,T2,T3;
        vector<double> mu1,mu2,mu3;
        vector<double> sigma_21,sigma_22,sigma_23;
        vector<double> S1,S2,S3;
        vector<double> p1,p2,p3;

        //read in 1st data file;
        FILE *in=fopen(argv[1],"r");
        char line[128];
        fgets(line,128,in); //skip the 1st row;

while (fgets(line,128,in))
{

                cout << line << endl;

                char *str = strtok(line, "\t");  // the space in  "\t" is a tab
                string marker(str);
                snp_list1.push_back(marker);

                str = strtok(NULL, "\t");
                location1.push_back(atof(str));

                str = strtok(NULL, "\t");
                freq1.push_back(atof(str));

                str = strtok(NULL, "\t");
                T1.push_back(atof(str));

                str = strtok(NULL, "\t");
                mu1.push_back(atof(str));

                str = strtok(NULL, "\t");
                sigma_21.push_back(atof(str));

                str = strtok(NULL, "\t");
                S1.push_back(atof(str));

                str = strtok(NULL, "\t");
                p1.push_back(atof(str));

        }
        fclose(in);

        //verify the vectors
        for (int i=0; i<snp_list1.size();++i)
                cout << snp_list1 << endl;
        return 0;

}

I tried to run the code but always met errors shown as  "error while
dumping state..(core dumped)".  I am new to C++.Thanks a lot for your
input.


You're welcome, but why disturb the gurus?

Start by not only including the fstream header, but also using the
classes it brings in - just get rid of FILE, fopen, fgets, strtok
etcetera.

Use your search engine and you'll get a lot of examples about reading
files with fstream & co.

Cheerio,
Francesco
 
E

Eric Pruneau

Seeker said:
Howdy, gurus

I want to write code to read in a large genomic file. The data look
like

Marker location freq T mu sigma_2 S p-
value
rs2977670 713754 0.925 779 9.604 141.278 2.202 0.02763
rs2977656 719811 0.992 793 9.120 134.796 2.733 0.00627

Here is my code:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

int main(int argc, char** argv)
{
vector<string> snp_list1,snp_list2,snp_list3;
vector<int> location1,location2,location3;
vector<double> freq1,freq2,freq3;
vector<int> T1,T2,T3;
vector<double> mu1,mu2,mu3;
vector<double> sigma_21,sigma_22,sigma_23;
vector<double> S1,S2,S3;
vector<double> p1,p2,p3;

//read in 1st data file;
FILE *in=fopen(argv[1],"r");
char line[128];
fgets(line,128,in); //skip the 1st row;

while (fgets(line,128,in))
{

cout << line << endl;

char *str = strtok(line, "\t"); // the space in "\t" is a tab
string marker(str);
snp_list1.push_back(marker);

str = strtok(NULL, "\t");
location1.push_back(atof(str));

str = strtok(NULL, "\t");
freq1.push_back(atof(str));

str = strtok(NULL, "\t");
T1.push_back(atof(str));

str = strtok(NULL, "\t");
mu1.push_back(atof(str));

str = strtok(NULL, "\t");
sigma_21.push_back(atof(str));

str = strtok(NULL, "\t");
S1.push_back(atof(str));

str = strtok(NULL, "\t");
p1.push_back(atof(str));

}
fclose(in);

//verify the vectors
for (int i=0; i<snp_list1.size();++i)
cout << snp_list1 << endl;
return 0;
}

I tried to run the code but always met errors shown as "error while
dumping state..(core dumped)". I am new to C++.Thanks a lot for your
input.


Here is a simple code to read some numbers in a text file using fstream and
stringstream

Here is my text file

SomeString 1 2 3 4 5


now I can read this like that

#include <fstream> // for ifstream
#include <sstring> // for istringstream
....


int main()
{
ifstream ifs("file.txt"); // this open the file in text mode by default

string strLine;
vector<int> v;

getline(ifs, strLine);
istringstream iss(strLine);
iss >> strLine; // extract the first element, we assume it is a string

// now loop until the end of the line and extract every integer
while(!iss.eof())
{
int tmp;
iss >> tmp;
v.push_back(tmp);
}
return (0);
}

It should be ewasy to modify that to read your file. Note that I didn't do
much error checking.

Eric
 
R

Ross A. Finlayson

"Seeker" <[email protected]> a écrit dans le message de (e-mail address removed)...


Howdy, gurus
I want to write code to read in a large genomic file. The data look
like
Marker          location   freq       T      mu     sigma_2  S       p-
value
rs2977670     713754   0.925     779   9.604 141.278   2.202  0.02763
rs2977656     719811   0.992     793   9.120 134.796   2.733  0.00627
Here is my code:
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
int main(int argc, char** argv)
{
vector<string> snp_list1,snp_list2,snp_list3;
vector<int>    location1,location2,location3;
vector<double> freq1,freq2,freq3;
vector<int> T1,T2,T3;
vector<double> mu1,mu2,mu3;
vector<double> sigma_21,sigma_22,sigma_23;
vector<double> S1,S2,S3;
vector<double> p1,p2,p3;
//read in 1st data file;
FILE *in=fopen(argv[1],"r");
char line[128];
fgets(line,128,in); //skip the 1st row;
while (fgets(line,128,in))
{
cout << line << endl;
char *str = strtok(line, "\t");  // the space in  "\t" is a tab
string marker(str);
snp_list1.push_back(marker);
str = strtok(NULL, "\t");
location1.push_back(atof(str));
str = strtok(NULL, "\t");
freq1.push_back(atof(str));
str = strtok(NULL, "\t");
T1.push_back(atof(str));
str = strtok(NULL, "\t");
mu1.push_back(atof(str));
str = strtok(NULL, "\t");
sigma_21.push_back(atof(str));
str = strtok(NULL, "\t");
S1.push_back(atof(str));
str = strtok(NULL, "\t");
p1.push_back(atof(str));
}
fclose(in);

       //verify the vectors
for (int i=0; i<snp_list1.size();++i)
cout << snp_list1 << endl;
       return 0;
}

I tried to run the code but always met errors shown as  "error while
dumping state..(core dumped)".  I am new to C++.Thanks a lot for your
input.

Here is a simple code to read some numbers in a text file using fstream and
stringstream

Here is my text file

SomeString 1 2 3 4 5

now I can read  this like that

#include <fstream>  // for ifstream
#include <sstring>   // for istringstream
...

int main()
{
     ifstream ifs("file.txt"); // this open the file in text mode by default

     string strLine;
     vector<int> v;

     getline(ifs, strLine);
     istringstream iss(strLine);
     iss >> strLine; // extract the first element, we assume it is a string

     // now loop until the end of the line and extract every integer
     while(!iss.eof())
     {
          int tmp;
          iss >> tmp;
          v.push_back(tmp);
     }
     return (0);

}

It should be ewasy to modify that to read your file. Note that I didn't do
much error checking.

Eric


If none of the columns have blank values, then the "input stream
extraction" with the >> operators will read in the data conveniently.
They skip whitespace and line endings.


ifstream input_file("filename");

string Marker;
int location;
double freq;
int T;
double mu;
....

while(!!input_file)
{
input_file >> Marker >> location >> freq >> T >> mu >> ...
}
input_file.close();

Then, where you also want to push those onto vectors, you can overload
the definition and build up the extractor for the vector of the type.

template <typename T> istream& operator>>(istream& in, vector<T>& vec)
{
T temp;
in >> temp;
vec.push_back(temp);
return in;
}

Then, as you've templatized the input extractor defined for a vector
of the type, it is more concise. That is where string and the built-
in types of int and double already have extractors defined.

#include <string>
#include <vector>
#include <iostream>
#include <fstream>

using std::string;
using std::vector;
using std::istream;
using std::ifstream;

vector<string> Markers;
vector<int> locations;
vector<double> freqs;
vector<int> Ts;
vector<double> mus;
// ...

template <typename T> istream& operator>>(istream& in, vector<T>& vec)
{
T temp;
in >> temp;
vec.push_back(temp);
return in;
}


void read_input_file()
{
ifstream input_file("file_name");

// read off the header
string header;
::getline(input_file, header);

// read off the lines
while(!!input_file)
{
input_file >> Markers >> locations >> freqs >> Ts >> mus >> ...;
}

input_file.close();
}

int main()
{
read_input_file();
return 0;
}

When evaluating input_file, it's an istream, ifstream : istream, and
it has the ! operator defined to return whether it has failed an
extraction (failbit), eg converting string to int, or gone into a bad
state (badbit), eg file error. There are some other semantics of the
input extraction.

If the columns entries had blank values, then that would be bad
because of reading a fixed number of columns into variables of
expected types.

Now, in terms of defining the vector extraction, that is where the
vectors are defined for the columns but the data is laid out in rows,
it's row-major instead of column-major. A different and reasonable
overload of the vector extractor would be along the lines of

template <typename T> istream& operator >> ( istream& in, vector<T>&
vec)
{
T temp;
while ( !!(in >> temp) vec.push_back(temp);
return in;
}

but that would always return, if it returned normally, with the eof,
fail, or bad bit set.

You might also want to define a record structure, and then define an
extractor for it.

struct record
{
string Marker;
int location;
double freq;
int T;
double mu;
// ...
};

then define the extractor for the record

istream& operator>>(istream& in, record& r)
{
return in >> r.Marker >> r.location >> r.freq >> r.T >> r.mu ; //...
}

then use it in the line reading loop with then the result being a
vector of records instead of a vector of vectors.

string header;
::getline(in, header);

vector<record> records;

while(!!in)
{
in >> records;
}

Now I might have made a mistake in the above but it is hopefully
correct.

Thanks,

Ross F.
 
R

Rune Allnor

while(!!input_file)
        while(!!input_file)
        while ( !!(in >> temp) vec.push_back(temp);
while(!!in)

Any reason for the consitent use of two exclamation marks?

Rune
 
R

Ross A. Finlayson

Any reason for the consitent use of two exclamation marks?

Rune

Then it's on program read interrupt.

The read of the buffer ready, adjusting the buffer, is misread on any
file misread option. It is to help preserve exception specification ,
on output read. Then, those could be annotated, for reinsertion into
the file handle clause for file event blocks on the transactional
signals. That's importantly reverifiable where the file mapping
blocks in the parameter block work on override read vector with the
addressing along remodularization.

About the double negative, that's where exception handling on the
record helps momentize the object vector. So, if you redefine it,
emulating its process record, it's cheaper to fill vectors off of the
read record.

Maybe it helps if it's really short,that "!!input_file" means read,
REED. Then, maybe that could work on STREAMS. Those are
computational so the redefine could help adjust system signal buffer.
It's the event of reading, to interpret the expression is to execute
the block. Streams are noncomputational. They're single message
channels. Then, that is about program record with the integrative and
positive error-correcting. What that means is as the exception record
is reduced or expanded the loop linear execution scalars on time-
series records amounts to exception record.

That's really too long an expression to say to stop the loop on the
loop read error. Reading the file, which is an input stream, into the
scalar record on the loop body pass, is a simple loop condition. The
idea of having the !input_file is to evaluate a boolean expression on
the istream which is an ifstream, file stream, and it's the input
extractor convention or one that I would depend on being defined to
evaluate on the file read into scalar (automatic constructor) branch.

Because it's redefined along with file record, along the
satisfiability chains of resultant recomputation, really I think this
makes sense, it helps to preserve the transactional moments back up
the stack on the build-up of the stack. Maybe that is so, in a
mannner of speaking. The point is about file record vis-a-vis
function grant with the process environment along natural error coding
which goes in to wait to process record.

Then, there are C extensions to mark the loop body with run, the
compilers have loop body markers off the standard, attributing run.

I look at this typing in the notepad window.

So, the double negative, the "not not input_file", means execute the
forward loop body because it is the while condition, an evaluated
expression.

The point is that it's a concise loop over the input record,
processing the file to load up the record. So, every time you run it
on a record that had already run it before, the exception record would
be absolutely expected. There the volatiles accumulate, in forward
area computationally integrative product expansion for preservation
back from reduction, but never on re-read static record, const.

Thank you,

Ross F.
 
J

James Kanze

"Seeker" <[email protected]> a écrit dans le message de (e-mail address removed)...

You need more specification than just a few example lines to be
able to write correct input. Are we guaranteed blanks between
each field? (What if a T is 12345.678, for example?) Are all
fields guaranteed to be present? What should we do in the case
of format errors?

[...]
Here is a simple code to read some numbers in a text file
using fstream and stringstream
Here is my text file
SomeString 1 2 3 4 5
now I can read this like that
#include <fstream> // for ifstream
#include <sstring> // for istringstream
...
int main()
{
ifstream ifs("file.txt"); // this open the file in text mode by default
string strLine;
vector<int> v;
getline(ifs, strLine);
istringstream iss(strLine);
iss >> strLine; // extract the first element, we assume it is a string
// now loop until the end of the line and extract every integer
while(!iss.eof())

This is incorrect, and will cause undefined behavior if the line
ends in white space. If you're just reading ints, then
something like:

while ( iss >> someInt ) ...

is the best solution.

In his case, the line had a defined format, something like
[string int double int int double] (or whatever); the easiest
way of handling this is:

struct Data
{
std::string field1 ;
int field2 ;
double field3 ;
int field4 ;
int field5 ;
double field6 ;
} ;

std::istream&
operator>>(
std::istream& source,
Data& dest )
{
source >> dest.field1 >> dest.field2 >> dest.field3 return source ;
}

and in main:

std::string line ;
int lineNumber ;
while ( std::getline( input, line ) ) {
++ lineNumber ;
std::istringstream parser( line ) ;
Data lineData ;
parser >> lineData >> std::ws ;
if ( ! parser || parser.get() != EOF ) {
if ( parser >> lineData >> std::ws && parser.get() == EOF) {
std::cerr << "syntax error, line " << lineNumber <<
std::endl ;
// Set flag so as to return EXIT_FAILURE from main.
} else {
// Date is good, process it...
}
}

Of course, you might want more error handling, to specify more
precisely what went wrong, but the above is often sufficient.

(The original poster very definitly should define a struct or a
class for his data, rather than keeping it in so many separate
vectors.)
{
int tmp;
iss >> tmp;
v.push_back(tmp);

Never, ever, use a value read from a stream without first
verifying that the read was successful.
}
return (0);

And never, ever return 0 if an error was encountered. (In
general, if the program outputs to std::cout, you should flush
it and test its status before returning success as well.)
 
J

James Kanze

Then it's on program read interrupt.
The read of the buffer ready, adjusting the buffer, is misread
on any file misread option. It is to help preserve exception
specification , on output read. Then, those could be
annotated, for reinsertion into the file handle clause for
file event blocks on the transactional signals. That's
importantly reverifiable where the file mapping blocks in the
parameter block work on override read vector with the
addressing along remodularization.
About the double negative, that's where exception handling on
the record helps momentize the object vector. So, if you
redefine it, emulating its process record, it's cheaper to
fill vectors off of the read record.

None of the above makes any sense to me, but one thing is
certain, most complers will generate exactly the same code with
or without the double exclamation. The double exclamation,
here, is basically a no-op, and has absolutely no effect on the
semantics of the program.
Maybe it helps if it's really short,that "!!input_file" means read,
REED.

No. !!input_file means "call the operator! function of
input_file, then complement the results". Without the !!, in a
conditional, "input_file" will be implicitely converted to bool,
and the results of implicitely converting it to bool are the
complement of the results of the operator! function. So all the
!! does is effectively complement the boolean value twice, which
is a no-op.

The usual idiom for reading a stream is:

while ( stream >> ... ) { /* ... */ }
or
stream >> ... ;
while ( stream ) {
/* ... */
stream >> ... ;
}

Anything else should only be used in exceptional cases.
 
A

Anton

On Sun, 2009-09-20 at 01:08 -0700, James Kanze wrote:

[...]
In his case, the line had a defined format, something like
[string int double int int double] (or whatever); the easiest
way of handling this is:

struct Data
{
std::string field1 ;
int field2 ;
double field3 ;
int field4 ;
int field5 ;
double field6 ;
} ;

std::istream&
operator>>(
std::istream& source,
Data& dest )
{
source >> dest.field1 >> dest.field2 >> dest.field3return source ;
}

and in main:

std::string line ;
int lineNumber ;
while ( std::getline( input, line ) ) {
++ lineNumber ;
std::istringstream parser( line ) ;
Data lineData ;
parser >> lineData >> std::ws ;
if ( ! parser || parser.get() != EOF ) {

// if ( parser >> lineData >> std::ws && parser.get() == EOF) {
// ^^^ This line should not be here, should it?
std::cerr << "syntax error, line " << lineNumber <<
std::endl ;
// Set flag so as to return EXIT_FAILURE from main.
} else {
// Date is good, process it...
}
}

[...]

Anton
 
R

Ross A. Finlayson

None of the above makes any sense to me, but one thing is
certain, most complers will generate exactly the same code with
or without the double exclamation.  The double exclamation,
here, is basically a no-op, and has absolutely no effect on the
semantics of the program.


No.  !!input_file means "call the operator! function of
input_file, then complement the results".  Without the !!, in a
conditional, "input_file" will be implicitely converted to bool,
and the results of implicitely converting it to bool are the
complement of the results of the operator! function.  So all the
!! does is effectively complement the boolean value twice, which
is a no-op.

The usual idiom for reading a stream is:

    while ( stream >> ... ) { /* ... */ }
or
    stream >> ... ;
    while ( stream ) {
        /* ... */
        stream >> ... ;
    }

Anything else should only be used in exceptional cases.


Here's some more about how to make that useful.


I think you can alias the record generally, and then composite their
record definition on the input extraction. This is where the idea of
the file record has that while it is a file stream, it is an input
stream, so the input extractors would then want to reinstrument scan,
scanning forward, that has to do with scanner interlock. It's in
reading the record, to satisfy recognition of the record on the
initial memoizations. That is where the scanner code with table block
for the dump tables beyond code space fill with the types reinstrument
scan. What that means is that in the processing of the table record,
where it is a tabular record, in this choice of an input read
expression for the input iterator combined with loop body buildup,
where the result of the vector has linear random access, has to keep
all the edge cases that build up, in quadrature. Then squares and
circles.

What does it mean, alias the record? The record is the logical
definition, so it is the table's specification. The table has a
specification. It is stored in a file, the data. That is about
distance of memory in space and time, on the computer. It takes
longer to access data on the file than in the buffer, and the buffer
is a shared read area. Then, in the memory hierarchy from the atomic
step registers to the cache memory through it's squaring regions, in
layers, to RAM over flash block, they are messages in the small.

Useful, to start making this useful, an idea is to actually make a
library to functionalize this thing.

The STREAMS are a POSIX thing where the socket or file for signal flow
is occurring, the streams serialize the timestamp data. Then it's in
time codes, but really it's about ignoring streams and maintaining
composability with them, in the auto extraction.

Building auto extraction, might help with auto extraction accumulation
on the loop expression share pool for the pool jump into process
buffer.

With the processing of the input file, you want it to recontinue and
process the rest of the record, pointing back to the failed read
record. So it just maintains statistics on the return of the read
record. Then, those are naturally formed indices on the stack block
forward the stack record, with the stack accumulator in the share swap
process memory read record.

With the concrete time and space terms with the way Knuth could
combined the fixed accumulator rates of proven assembly language
machines, he uses a 256 code for the instruction number of so from the
instruction dictionary, of sorts, where that has hopefully a way to
build into it with instrinsics and maybe even auto replacements that
accumulate the composable and reversible or removable or quantumly
accumulated. Lots of assembly languages are that way, Fixed width
fixed size instruction list, with instruction counting. (Rise/fall.)

Really though, why would something like that be useful. Here's maybe
a help. There is lots of source code that uses files. Where is the
google tool to find source code uses of the pattern and show what
files conditions, those are read conditions, give the input to the
record storage. The use of the ::getline() function, for example, to
read the row record list header, has in the maintenance of the linear
forward address space of the random linear address, would maybe better
be "read_table_header()", then where for example XML containing table
records in an XML envelope in digital messaging, could have schema
verified the statement that is some tabular recognition, where then
the XML parser statistics would inform the parser instructions. That
is in a sense about defining that each of the set of instructions or
data files that were ever read have their instruction record either
read or not read. The "read_table_header()" function calls "::getline
()", that's what to compose so that after you take the header off, it
can be put back, with the spacing under the headers.

read_table_header(input_file);

while(!!input_file)
{
read(record);
}


Or, for example

read(input_file);

while(!!input_file)
{
input_file.record();
}

Yet, the code shouldn't be a non-templated thing if it could be made a
template about ifstream, particularly for example, say I/O controls on
register banks for control bank update. To templatize the algorithm,
is partially to separate the algorithm.

// specialize
typedef default

file_specification

enum file_specification_type_t
{

};

class file_name_forward_t = const char*;
typedef file_name_t file_name_forward_t;

static const filename_t filename_default = default;

vector_loop_serial_records(filename_t& filename)

try
{
ifstream input_file("filename"); // <- literal is convertible

if (!!input_file);
// <- with !input_file or input_file.is_open(), read ready, off
constructor defaults, "input" fstream
// methods of istream are expected to be
// called on file stream, here mark template boundary
// could also be input_file() when this "try" block has its types
collected.
{
try
}
while (!!inputfile) // <-
{
inputfile >> record; // <- the function to be composed to read the
records

}
catch (...)
{

}
catch(exception& e)
{

}
catch(exception e)
{

}
finally
{

}
}

}
catch(...) // <- wait to crunch the cancel on the transaction record
catch (exception e) // <- local exception? templatize
{

}

Then, the result of calling this function is that the row records of
the tabular data are in the random linear access vector, which gets
distributed in its loading into memory when it grows past word
boundaries, with memory barriers.

Is there a C++ collection base?

Here's another reason to use "!! input_file", "! ! input_file", it can
contain the exception handlers as well because for the template
generation there is the type, so that is the point about making it a
template with a typename in the template beyond just the class
definition. Different than "!! input_file()", maybe illegal. IT
could be a pointer or reference type, then, it could cast out of the
template with the template set chain handlers, to, then perhaps handle/
body, pointer to implementation?

template <class T>

template <typename T>

Then, maybe the typename is the file name, then the operators are
static and local, the input extraction operators, they're the
parameter block description.

Then the type transforms are serialized for simple maintenance or
maintainence of the pre-computed block with the input test validation.

Then, in the resource aquisition on the resulting data read, it's
forward error correcting, so the steps back up to the database
execution wait buffer , has the empty auto-constructors just off the
small scalar composite recomputes.

Idea is to snap back to scale on empty record adjustment.

Set the error handler with the fix for the record, that way the parser
restarts by signaling its own data path in the streams, on the
adjusted recompute or accompanying recompute on the record, just for
the maintainance of the timestamp banks, for forward statistical
postive error correction integrated
..
That is why maybe it's useful to maintain the template, and then make
the template for the file stream, with its name, where, this is where
the Original Poster, he is reading the file. Some else compiled the
data and stored it in the file. It's worth it for the reader to read
the file manually if that is convenient to do so.

Making the typename extension with the template cancelling on the
error-free cancellation of the template projections and extensions,
here maybe C++ does not have that in setting the exception handlers
for the function's stack autodefining on empty address offset the
object handle on the signal with the stream signal. This is about
making the call instead of

ifstream input_file ( "input.txt"); // <- what about input

filename_t input_identifier_type;
ifstream input_file(input_identifier_type); // <- input_file is an
input, here are the template extensions for input stream interface,
read.

template <class istream&, class filename_t> // <- reuse definitions
This should instead be with typename.

read_function(){
{
class istream reference; // <- use all the auto computed with the
const along reducing to signal catching
class filename type; // <- it's a class, you can use it in a template
to define automatic classes they are statically loaded.

filename::filename();

filename::

}

Then be sure not to define the read functions except for the compiler
has to generate more templates or else it would cancel, because:
there's not enough specification. Leave the input on the stack for
the local sidestep recompute in the reference vector, that goes in and
out of the process bank, with the unit step. The types that are
specialized when there isn't the input cancellation solve to re-
autodefine, because of simple maintenance of input record. Why is it
filename, it is the input indentifier, then the function is processed
in the run body, redefining run(), in anonymous run-body annotation
with the execution continuance. No, that is not how types can be used
in the forward definition of intrinsic references?

With read, that is part of bringing the data from getting the data
with again the template relaxation, with not cancelling compilation,
accomodating const re-reference, with path enumeration back up the
input record. Then, it would be nice if compilation then reflected on
the input data serialization and what happens is that it maintains
small diagrams which is then about using source code, that, you can
use later from source code.

That's just an example of the use of the reflective method body
compilation on the translation graph with the programming.

Then , say I want to write a program to convert a PDF generated from
TeX back to TeX source. Then, it's a good idea to automated the
generation of the transform. Take the PDF, and make it into the
correct TeX format. To submit my paper to arxiv, it's rejected
because it's a PDF file generated form TeX so I am supposed to submit
the original .TeX source code file, \TeX. I think I lost that data
but it might be on the disk image with the disk repartition. So, what
I wonder about are disk records with the copy of it.

On the input stack, add, check all the input parameters as a scalar
record, if they are the same input then return the static input

so, just there have an auto refinement stack that caches all the
record with the definition of all the equality satifiers over the
product space of the inputs, in that way, maintaining the chains of
function referred aliases with the permutation and transposition
generation. The indentical inputs cache the return value, but then
for that not just to be whatever it costs to execute the operation to
compare the input to the previous invocations', then it should
probably be written next, where this is about the development of the
execution stack in the automatic memory of the function prolog. If
that matches in the shift-matching, only actually matching a totally
identical input record to the previous output of the function, with
the content associative memory, that requires multiple copies of space
for the input record on the function's automatic local stack. Then,
if the functions is serializing the return values for the "NOT"
functions, abbreviated to the exclamation point !, bang, "!!!!!!",
NOT, then those functions return under the sharing with the input
parameter block stack for the catalog of the identical input vector.
Then in the loop, it is about where generally the record is row
identical because it's unique. Imagine reading the same file over and
over again, just adding to the same collection of records. Then the
records are accounts of the reads, there are some cases where, it is
not clear how to identify the local scalar offset with the
identification with the loop branch to record comparing to previous
instruction stream, in the matching along the input record.

Then, set the archive bit on the file, when it is computed that it
should be the same, given identical input subsets. Those are sampled
when the scanner snapshots for the archive bit on the file? Then
those could help represent dropouts on the file.






Thank you,

Ross F.
 
J

Jerry Coffin

Any reason for the consitent use of two exclamation marks?

I'm not sure why _he's_ doing it, but it's an old C trick for
converting from int to bool -- i.e. zero stays zero, but any non-zero
value becomes a one.
 
R

Ross A. Finlayson

I'm not sure why _he's_ doing it, but it's an old C trick for
converting from int to bool -- i.e. zero stays zero, but any non-zero
value becomes a one.

There is already an overload of istream to convert it to bool.

#include <iosfwd>
std::istream in;

if(in) 0; // calls the globally defined complement operator
// that checks the istream state, rather istream typeconverts
// which is implemented as !

if(!!in) 0; // could it be overriden to another that returns that
converts to bool ?

class boolean_evaluable
{
operator ()(bool& b){b = true;}
}

boolean_evaluable& operator !(istream& in){}

if(!!in) 0; // different?

One would think that the iostream operator would be resolved first to
be the maybe class-defined type, the complement operator is overloaded
as a member function of iostream. If the function was otherwise
resolved to be the overload for the istream that returns a
boolean_evaluable, then the identical source code statements could
have different effects from template inclusion. Then, if "in" was
some in-place input stream with the layout in an object, the user
could activate code with the extra double-negative pairs that are no-
ops.

Sure, the syntax above might actually not be ISO C++ but it seems that
it might be, wondering if it should "(void)0" instead of "0" and
whether it's ISO C++ if the compiler can erase the loop.

It seems an idea about trying to autogenerate the composite inserters
and extractors via the careful observance of the semantics of the I/O
streams, and re-implementing them, with compile-time support of the
generation of the class framework, so to say, there isn't much of a
class framework as really just some templates that collapse leaving
behind type converters that the language interpreter compiles per
unit, where there's quite a large template class framework where the
idea is to templatize functions around the parent types of the
template typename types, to automatically generate the inserters and
extractors from C variables and structs, with the notion of not having
standard includes on the file, defining templates around the built-in
types, including the standard includes, then for some reason canceling
the templates yet not those that were generated afterwards from the
legacy classes, with the temporary templates.

Regards,

Ross F.
 
J

James Kanze

I'm not sure why _he's_ doing it, but it's an old C trick for
converting from int to bool -- i.e. zero stays zero, but any
non-zero value becomes a one.

Yes, but there's no need for doing it in a condition, even in
old C. (In C++, of course, the "correct" way of doing this
would be to explicitly convert to bool.)
 
J

James Kanze

There is already an overload of istream to convert it to bool.

No. For historical reasons, there is an implicit conversion to
void*, not to bool. Logically, however, it works as if it were
an implicit conversion to bool, and there's nothing you can
really do with resulting void* except convert it to bool or
compare it with NULL.
#include <iosfwd>
std::istream in;
if(in) 0; // calls the globally defined complement operator
// that checks the istream state, rather istream typeconverts
// which is implemented as !

No. It tries to implicitly convert in to type bool. And
succeeds, by calling the user defined conversion operator
void*(), then converting the resulting pointer to bool. There's
no complement operator involved at all.
 
J

James Kanze

[...]
In his case, the line had a defined format, something like
[string int double int int double] (or whatever); the easiest
way of handling this is:
struct Data
{
std::string field1 ;
int field2 ;
double field3 ;
int field4 ;
int field5 ;
double field6 ;
} ;
std::istream&
operator>>(
std::istream& source,
Data& dest )
{
source >> dest.field1 >> dest.field2 >> dest.field3
dest.field4 >> dest.field5 >> dest.field6 ;
return source ;
}
and in main:
std::string line ;
int lineNumber ;
while ( std::getline( input, line ) ) {
++ lineNumber ;
std::istringstream parser( line ) ;
Data lineData ;
parser >> lineData >> std::ws ;
if ( ! parser || parser.get() != EOF ) {
// if ( parser >> lineData >> std::ws && parser.get() == EOF) {
// ^^^ This line should not be here, should it?

It should be simply:

if ( parser ) {

An editing error.
 
J

Jerry Coffin

On Sep 21, 2:59 pm, Jerry Coffin <[email protected]> wrote:

[ ... ]
Yes, but there's no need for doing it in a condition, even in
old C.

Exactly -- that's why I emphasized that I don't know why _he's_ doing
it. Under the circumstances, it accomplishes nothing.

When used in C, it was typically for things like using the result as
a subscript in an array, where it was important that any true value
was converted to 1.

It's also probably good that you emphasizes "old C" -- the current C
standard also has a boolean type, so if you're using that (i.e. if
your compiler implements it) you'd probably want to convert to bool
(or _Bool) in current C as well.
 

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