C/stdlib.h/Exit 2
_Exit: exit program without closing files
//Declaration: void _Exit(int exit_code);
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
char choice;
do {
printf("Quit (Q)\n");
choice = getchar();
} while(!strchr("Q", toupper(choice)));
if(choice=="Q"){
_Exit(0);
}
return choice;
}