exit : exit « stdlib.h « C Tutorial

1. C Tutorial
2. stdlib.h
3. exit

Termination functions registered by atexit() are called, and any open files are flushed and closed.

1. The value of exit_code is passed to the calling process.
2. If the value of exit_code is zero, or EXIT_SUCCESS, normal program termination is assumed.
3. A nonzero value, or EXIT_FAILURE, is used to indicate an implementation-defined error.

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

  int main(void)
  {
    char choice;

    do {
      printf("Enter names (E)\n");
      printf("Delete name (D)\n");
      printf("Print (P)\n");
      printf("Quit (Q)\n");
      choice = getchar();
    } while(!strchr("EDPQ", toupper(choice)));

    if(choice=='Q') exit(0);

    return choice;
  }