Hi all, so I literally picked up a book (actually several) and decided to learn C today and I can't figure out what is wrong with the source code of a program the book just had me write.

My problem is this: the program is supposed to take the source code of other files and print them to the screen with with line numbers for the lines of code. The binary I produced executes, but when I try using the program by typing at a blank command prompt for example C:...> print_it hello.cpp, all I get is Page 1, hello.cpp and then a Windows button telling me that print_it has encountered an error and needs to close.

I thought that the problem might be with how I copied the source code from the book into my editor, but I have double-checked that, so I thought I'd post it here and see if anyone can help me.

Thanks,

/* print_it.c-- This program prints a listing with line numbers! */
#include <stdlib.h>
#include <stdio.h>

void do_heading(char *filename);

int line = 0, page = 0;

int main( int argv, char *argc[] )
{
char buffer[256];
FILE *fp;

if( argv < 2)
{
fprintf(stderr, "\nProper Usage is: ");
fprintf(stderr, "\n\nprint_it filename.ext\n" );
return(1);
}

if (( fp = fopen( argc[1], "r" )) == NULL )
{
fprintf( stderr, "Error opening file, %s!", argc[1]);
return(1);
}

page = 0;
line = 1;
do_heading( argc[1]);

while( fgets( buffer, 256, fp ) != NULL )
{
if( line % 55 == 0 )
do_heading( argc[1] );

fprintf( stdout, "%4:\t%s", line++, buffer );
}

fprintf( stdout, "\f" );
fclose(fp);
return 0;
}

void do_heading( char *filename )
{
page++;

if ( page > 1)
fprintf( stdout, "\f" );

fprintf( stdout, "Page: %d, %s\n\n", page, filename );
}

Just a typo in your coding...
Check the red "d" in there...

/* print_it.c-- This program prints a listing with line numbers! */
#include <stdlib.h>
#include <stdio.h>

void do_heading(char *filename);

int line = 0, page = 0;

int main( int argv, char *argc[] )
{
char buffer[256];
FILE *fp;

if( argv < 2)
{
fprintf(stderr, "\nProper Usage is: ");
fprintf(stderr, "\n\nprint_it filename.ext\n" );
return(1);
}

if (( fp = fopen( argc[1], "r" )) == NULL )
{
fprintf( stderr, "Error opening file, %s!", argc[1]);
return(1);
}

page = 0;
line = 1;
do_heading( argc[1]);

while( fgets( buffer, 256, fp ) != NULL )
{
if( line % 55 == 0 )
do_heading( argc[1] );

fprintf( stdout, "%4d:\t%s", line++, buffer ); // <-- HERE
}

fprintf( stdout, "\f" );
fclose(fp);
return 0;
}

void do_heading( char *filename )
{
page++;

if ( page > 1)
fprintf( stdout, "\f" );

fprintf( stdout, "Page: %d, %s\n\n", page, filename );
}

Check how fprintf() works, in your book.

Good luck!
Hackman