How to start a program using another program?

[Netaro]

Well...
So, i have a program. A normal program, which does something, and so..
and i have another program, which wants to run the first program....
So, there are 2 questions about that problem ->
1) How can i run the program using another program? Is there anything like runProgram(Directory,Name.exe)?
2) Programs usually returns the 0 value when they end. So, can i, for example, put something like

int main(){
int something;
//do something to the variable something
return something;

and get the value using another program?

[horace1]

you can use the system() function in C and C++, e.g.

#include <stdio.h>
#include <process.h>
 
int main(void)
{
    system("dir *.c");                                         /* call system */
    printf("parent program resumed");
    return 0;
}
 

the parent process is suspended, the child process runs, when child stops parent resumes

If you want to run concurently use spawnl()