fgets cant read string object

[desijays]

I cant seem to read info from a file into a string object using fgets?

Could someone point out the problem to me? Heres the code..Its quite small



ptr_ArtAsset = fopen( "C:\\Desktop\\DESKTOP\\SDL\\Debug\\resource.txt", "rt" );

if( ptr_ArtAsset )
std::cout << "file opened\n";


fgets( const_cast<char *>(obj_path.c_str()), obj_path.capacity(), ptr_ArtAsset );
std::cout << obj_path;

if( !(fclose( ptr_ArtAsset )) )
std::cout << "file closed\n";


Or if not 'fgets'.......is there any other alternative?

[aks44]

Could someone point out the problem to me? Heres the code..Its quite small


const_cast<char *>(obj_path.c_str())

The prototype of c_str() is const char* std::string::c_str() const for a good reason.

Note the two consts, they mean that:
1) c_str() does not modify the object (this is the second const at the end of the definition)
2) it returns a pointer to const characters, ie. you MUST NOT even try to modify the pointed-to data.

Again, the compiler gave you an error for a good reason. Getting rid of an error in the dirtiest way (here, a cast) is generally not the way to go.

Your problem comes from the fact that you're trying to mix C code with C++.
Get rid of those fopen / fgets / fclose, and use ifstream (in <iostream>) as your input file. ;)


If you have a C background as I suspect, I'd recommend you to unlearn C for a moment, until you can really grasp C++ concepts. Just because C++ can do the same as C and way more doesn't mean the C concepts must be used blindly.

BTW Bruce Eckel's Thinking in C++ (http://mindview.net/Books/TICPP/ThinkingInCPP2e.html) might be a good read for you (and it is available both as hard cover and as a PDF download).

[manimal]

Does the code output anything? I am not so familiar with C++, but this C code works for me:


#include <stdio.h>
#include <stdlib.h>

#define STR_LEN 1000

int main() {
FILE *ptr_ArtAsset=NULL;
char str[STR_LEN];

ptr_ArtAsset = fopen( "Put_file_name_here", "rt" );

if( ptr_ArtAsset )
printf("file opened\n");

while (!(feof(ptr_ArtAsset))) {
fgets( str, STR_LEN, ptr_ArtAsset );
printf("%s",str);
}

if( !(fclose( ptr_ArtAsset )) )
printf("file closed\n");

return EXIT_SUCCESS;
}

I agree with the above poster that you should really try to avoid mixing C and C++ unless you know what you are doing. I think my advice might be to forget all the C++ nonsense though and just use plain C. :)