#include <stdio.h>
#include <string.h>

int main(int argc, char*argv[])
{
     int nRC = 0;
     char today[20];
     memset(today, 0, 20);
     // get the command line of day
     if(argc > 1)
     {
           strncpy(today, argv[1], 20);
     }

     if( strcmp(today, 'thursday')==0)
     {
           printf("42!\n");
     }
     else
     {
           printf("Error in computation or input. Try again.\n");
           // tell calling system that we are MASSIVE FAIL
           nRC = -1;
     }
     return nRC;
}

with <someobject> do:
      foo()

// instead of 
<someobject>.foo();