Puzzle SL50

External sum

Here the variable sum is shared between two files:

 
/* --- sumVersion10.c --- */

int sum;

int sumInts( int limit )
{
  sum = 0;  
  int j;

  for ( j=1; j<=limit; j++ )
  {
    sum += j;
  }

}
 
/* --- sumDriver10.c --- */
#include <stdio.h>
int sum;
int sumInts( int x );

void main()
{   
  sumInts( 10 );
  printf( "sum of 1..10: %d\n", sum );    

  sumInts( 5 );
  printf( "sum of 1..5: %d\n", sum );    
}

Compile and run the two files:

gcc sumDriver10.c sumVersion10.c
a.exe

Is this going to work?