Running two different programs from a single program.

Posted on 1998-09-10
Last Modified: 2010-04-15
I have two different C progams named factor.c and index.c
I want to write a 3rd program which when run will show two options: "Press F for Factor program"
         "Press I for Index program"
While I press "F" the factor.c progam should run, and while
I press "I" index.c should run.
Pls let me know how to write the 3rd progam say combine.c?
Question by:saurav

Expert Comment

ID: 1252632
There are two options:
1) to combine everything in one executable.
2) to create 3rd executable that will start either one of factor and index depending on the selection.

LVL 11

Expert Comment

ID: 1252633
saurav, a C program may consist of several source files.

As Bonev noted, you can combine all the files into one program thus:
  factor.c will contain a function called Factor()
  index.c will contain a function called Index()
  combine.c will contain your main() function that will invoke one of the other functions.
Don't forget to add an include file (say, combine.h) that will contain the prototypes for both functions.

If you really want to treat all three as different programs, you can use the system(), execl() or spawnl() functions to execute another program.

Accepted Solution

duneram earned 50 total points
ID: 1252634
assumptions:  factor.c when compiled is factor.exe
                     index.c when compiled is index.exe

This example, won't exit until the user presses E to exit.


int main(int argc, char *argv[])
   char x;

   while (1)
      printf("Press F for Factor program\nPress I for Index program\n");
      printf("Press E to exit the program\n\n");
      x = getc(stdin);
      if (x == 'E')
            printf("Exiting the program.  Thanks for using me\n");
             break; /* get out */
      if (x == 'F')
         printf("Executing the factor program\n");
         system("factor.exe");  /* execute the factor program */
      if (x == 'I')
         printf("Executing the Index program\n");
         system("index.exe");  /* execute the index program */
   } /* end while */

   return 0;

Expert Comment

ID: 1252635
at the top of combine.c you will most likely need

#include <stdio.h>
#include <stdlib.h>

Alexo:  When I was doing the code above, you hadn't posted so I never saw it.  one of those timing things...

But that's the way the ball bounces sometimes.

Author Comment

ID: 1252636
Hi all,
Thanks everybody for replying. The codes 'duneram' wrote for me worked perfectly. Thank you very very much.Saurav

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