S
silly
/*Thanks again to thos who helped with my
'more hand written integer pow() functions (LONG POST)' query.
I needed to write a function to write out integers and after looking at some
stuff
on the web I felt they look a bit code-heavy so...
A) If you think the code attached is reasonable, consider it a donation,
if not please lets have your comments!
The recursive pow() inspired my first attempt which looks pretty good
to me but if you see an improvement feel free. I have attempted to make
an iterative version. I wondered if there were some obvious ways of
making
it more concise.
B) An answer to the malloc query in comments in the code (after 'int
stack[3];')
would be helpful too.
Perhaps considering the following will show what I mean better...
slightly different scenario to the main code appended, here im looking
at strings. if you have:-
binstr ="101010101010101010....010101001111111"
and a function binstr_to_intstr() to create:-
intstr ="125663....137373077"
assuming you could fit intstr into an int and used pr_numi, how would
you accurately calculate the size of array needed based on the size of
binstr?
How would you declare/allocate/use the array/memory/pointer?
stack[0]=77
stack[1]=373
stack[2]=137
...
stack[n-1]=663
stack[n]=125
*/
/*--------------------start of code---------------*/
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#define PR(x) printf(#x " = %d ",x)
#define NL putchar('\n')
#define SP putchar(' ')
#define DELIM ","
#define iabs(x) ( (x)>0?(x):-(x) )
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* recursive version...*/
void pr_numr( int x)
{
if (iabs(x)<1000)
printf("%3d", x);
else
{
pr_numr(x/1000);
printf(DELIM "%03d", iabs(x%1000));
}
return;
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* iterative version...*/
void pr_numi( int x)
{
int stack[3];
/*the '3' should be related to sizeof(int) (i.e. one less than?) or
some formula with lots of nice shifts?, use malloc?*/
int i=0;
if (iabs(x)<1000)
printf("%3d", x);
else
{
do {
stack[i++] =x%1000;
x/=1000;
} while (iabs(x)>1000);
printf("%3d", x);
while(--i>=0)
printf(DELIM "%03d", iabs(stack));
}
return;
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
int main(int argc, char **argv)
{
int x, i,m,t[] = {0, 1, 12, 123, 999,1000, 1234, 1034,
12034, 12009880, 1123034783, INT_MAX};
m= sizeof(t)/sizeof(int);
if (argc==1)
for(i=0;i<m;i++)
{
x=t;
printf("%20d: ", x);
pr_numr(x);
printf("\n%20s ", " ");
pr_numi(x);
NL;
NL;
/*now try the -ve*/
x=-x;
printf("%20d: ", x);
pr_numr(x);
printf("\n%20s ", " ");
pr_numi(x);
NL;
NL;
}
else
while(--argc>0)
{
printf("%20d: ", atol(*++argv));
pr_numr(atol(*argv));
printf("\n%20s ", " ");
pr_numi(atol(*argv));
NL;
}
return 0;
}
/*--------------------end of code-----------------*/
'more hand written integer pow() functions (LONG POST)' query.
I needed to write a function to write out integers and after looking at some
stuff
on the web I felt they look a bit code-heavy so...
A) If you think the code attached is reasonable, consider it a donation,
if not please lets have your comments!
The recursive pow() inspired my first attempt which looks pretty good
to me but if you see an improvement feel free. I have attempted to make
an iterative version. I wondered if there were some obvious ways of
making
it more concise.
B) An answer to the malloc query in comments in the code (after 'int
stack[3];')
would be helpful too.
Perhaps considering the following will show what I mean better...
slightly different scenario to the main code appended, here im looking
at strings. if you have:-
binstr ="101010101010101010....010101001111111"
and a function binstr_to_intstr() to create:-
intstr ="125663....137373077"
assuming you could fit intstr into an int and used pr_numi, how would
you accurately calculate the size of array needed based on the size of
binstr?
How would you declare/allocate/use the array/memory/pointer?
stack[0]=77
stack[1]=373
stack[2]=137
...
stack[n-1]=663
stack[n]=125
*/
/*--------------------start of code---------------*/
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#define PR(x) printf(#x " = %d ",x)
#define NL putchar('\n')
#define SP putchar(' ')
#define DELIM ","
#define iabs(x) ( (x)>0?(x):-(x) )
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* recursive version...*/
void pr_numr( int x)
{
if (iabs(x)<1000)
printf("%3d", x);
else
{
pr_numr(x/1000);
printf(DELIM "%03d", iabs(x%1000));
}
return;
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* iterative version...*/
void pr_numi( int x)
{
int stack[3];
/*the '3' should be related to sizeof(int) (i.e. one less than?) or
some formula with lots of nice shifts?, use malloc?*/
int i=0;
if (iabs(x)<1000)
printf("%3d", x);
else
{
do {
stack[i++] =x%1000;
x/=1000;
} while (iabs(x)>1000);
printf("%3d", x);
while(--i>=0)
printf(DELIM "%03d", iabs(stack));
}
return;
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
int main(int argc, char **argv)
{
int x, i,m,t[] = {0, 1, 12, 123, 999,1000, 1234, 1034,
12034, 12009880, 1123034783, INT_MAX};
m= sizeof(t)/sizeof(int);
if (argc==1)
for(i=0;i<m;i++)
{
x=t;
printf("%20d: ", x);
pr_numr(x);
printf("\n%20s ", " ");
pr_numi(x);
NL;
NL;
/*now try the -ve*/
x=-x;
printf("%20d: ", x);
pr_numr(x);
printf("\n%20s ", " ");
pr_numi(x);
NL;
NL;
}
else
while(--argc>0)
{
printf("%20d: ", atol(*++argv));
pr_numr(atol(*argv));
printf("\n%20s ", " ");
pr_numi(atol(*argv));
NL;
}
return 0;
}
/*--------------------end of code-----------------*/