#include <iostream>
using namespace std;
int main() {
auto run = true;
int choice;
while (run) {
cout << "choice: ";
cin >> choice;
cin.ignore(0x1000, '\n'

;
switch (choice) {
case 1: puts("one..."

; break;
case 2: puts("two..."

; break;
case 3: puts("three..."

; break;
case 4: run = false; break;
default: puts("error!"

; break;
}
}
puts("exit"

;
}