passing an iterator as an argument

[Gary Wessle]

Hi

I am trying to pass a iterator to a function, this is the iterator and
what it does

typedef vector<string>::const_iterator vs_itr;
for(vs_itr i=vect.begin(); i!=vect.end(); ++i){
x = fix_it(*i, 2.0);
..

// fix_it(string* 1.235, 2.0) returns double 1.24
double fix_it(vector<string>::const_iterator s, double n){
double y = strtod(s->c_str(),0);
return floor( y*pow(10,n) + 0.5 ) / pow(10,n);
}

I am getting an error relating to the type problem

****************************************************************
no matching function for call to

&, double&)'

gen_data.h:27: note: candidates are:
double gen_data::fix_it(__gnu_cxx::__normal_iterator<const

*, std::vector<std::basic_string<char, std::char_traits<char>,

std::allocator<char> >, std::allocator<std::basic_string<char,
std::char_traits<char>, std::allocator<char> > > > >, double)
****************************************************************

I tried to fix it by redefining the first argument of the function so
that it is a const vector<string>::const_iterator but that did not fix
it.

 

[Noah Roberts]

Hi

I am trying to pass a iterator to a function, this is the iterator and
what it does

typedef vector<string>::const_iterator vs_itr;
for(vs_itr i=vect.begin(); i!=vect.end(); ++i){
x = fix_it(*i, 2.0);

Should be fix_it(i, 2.0), no?

 

[Daniel T.]

Hi

I am trying to pass a iterator to a function, this is the iterator and
what it does

typedef vector<string>::const_iterator vs_itr;
for(vs_itr i=vect.begin(); i!=vect.end(); ++i){
x = fix_it(*i, 2.0);
..

// fix_it(string* 1.235, 2.0) returns double 1.24
double fix_it(vector<string>::const_iterator s, double n){
double y = strtod(s->c_str(),0);
return floor( y*pow(10,n) + 0.5 ) / pow(10,n);
}

The best solution would be:

double fix_it( const string& s, double n ) {
double y = strtod( s.c_str(), 0 );
return floor( y * pow( 10, n ) + 0.5 ) / pow( 10, n );
}

In other words, don't pass an iterator to a function unless you need to
features that the iterator provides.

If you must do so, then:

for ( vs_itr i = vect.begin(); i != vect.end(); ++i ) {
x = vix_it( i, 2.0 );
// note the asterisk isn't in the above line.