Difference between revisions of "C programming quick start"

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(Created page with " '''#include <stdio.h>''' The #include is a "preprocessor" directive that tells the compiler to put code from the header called stdio.h into our program before actually crea...")
 
Line 25: Line 25:
 
gcc hello.c -o hello
 
gcc hello.c -o hello
  
'''running hello world'''
+
'''run hello world and check exit status of last command'''
  
 
  $ '''./hello'''
 
  $ '''./hello'''

Revision as of 20:43, 10 July 2014

#include <stdio.h>

The #include is a "preprocessor" directive that tells the compiler to put code from the header called stdio.h into our program before actually creating the executable

int main() { }

Main body of program. Returns integer exit status to O.S. after execution. 0 = success, non zero is an error message.

hello world example

  1. include <stdio.h>

int main() {

   printf( "Hello world!\n" );
   printf( "(hit enter to end)\n" );
   getchar();
   return 0;

}

compiling with gcc

gcc hello.c -o hello

run hello world and check exit status of last command

$ ./hello
Hello world!
(hit enter to end)

$ echo $? 0 $ ./hello Hello world! (hit enter to end) ^C $ echo $? 130