Cannot Execute/Run Program
Hi everyone,
I am new to the board and not really a programmer yet but I found this book SAMS Teach Yourself C in 21 Days by Bradley Jones and Peter Aitken, so I decided to just get my head around it. I would like to have some knowledge on C somehow as I may need it in my profession in the future.
The problem is with the first "Type and Run," where the code looks like this:
Code:
/* 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( stdprn, "%4d:\t%s", line++, buffer );
}
fprintf( stdprn, "\f" );
fclose(fp);
return 0;
}
void do_heading( char *filename )
{
page++;
if ( page > 1)
fprintf( stdprn, "\f" );
fprintf( stdprn, "Page: %d, %s\n\n", page, filename );
}
I am using the gcc compiler in Ubuntu 12.04 LTS and I get the following error:
Code:
print_it.c: In function ‘main’:
print_it.c:36:15: error: ‘stdprn’ undeclared (first use in this function)
print_it.c:36:15: note: each undeclared identifier is reported only once for each function it appears in
print_it.c: In function ‘do_heading’:
print_it.c:49:16: error: ‘stdprn’ undeclared (first use in this function)
I was told that "stdprn" can be recognised by a DOS based compiler and the book says I can try using "stdout" instead. It looks like this now:
Code:
/* 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 );
}
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 );
}
It compiled OK with the gcc compiler but I only get this when I run the program:
Code:
Proper Usage is:
print_it filename.ext
I am not sure whether I should continue looking into this but even when I tried compiling and running it on Windows, the .exe file won't even launch. The other ones do but this first one doesn't.
Questions:
1. What should be done to make this program run?
2. Even though the book says "don't care" if the reader does not understand the items (It's Day 1/Lesson 1), I would still like it to run as I don't want to experience compiling and running problems in the future. Should I even bother doing this section of the book or is it obsolete and should be skipped?
Thanks.
