exit function

void exit_phonebook()
{
    char confirm[100];
    char yes[3]="yes";
    char Yes[3]="Yes";
    printf("Are you sure you want to exit? (Yes or No)\n");
    scanf("%s", confirm);
    if (strcmp(confirm,Yes)==0||strcmp(confirm,yes)==0)
        exit(0);
    else
        display_menu();
}