명품 C++ Programming 실습문제 7장 10번

#include <iostream>
using namespace std;
 
class Statistics {
    int *stack;
    int index;
public:
    Statistics() { stack = new int[100]; index = 0; }
    ~Statistics() { delete[]stack; }
    Statistics& operator<<(int x);
    bool operator!();
    void operator>> (int &x);
};
 
Statistics& Statistics::operator<<(int x) {
    stack[index] = x;
    index++;
    return *this;
}
 
bool Statistics::operator!() {
    if (index == 0) return true;
    else return false;
}
 
void Statistics::operator>>(int &x) {
    x = stack[index - 1];
    index--;
}
 
int main() {
    Statistics stack;
    stack << 3 << 5 << 10;
    while (true) {
        if (!stack) break;
        int x;
        stack >> x;
        cout << x << ' ';
    }
    cout << '\n';
}