28-题目1108：堆栈的使用

http://ac.jobdu.com/problem.php?pid=1108

题目比较简单

#include<stdio.h>#include<string.h>#include<fstream>#include<iostream>using namespace std;int main(){int n;ifstream cin("data.txt");while (cin >> n && n !=0 ){int i, tail = -1;char operation;int *stack = new int[n];for (i = 0; i < n; i++){cin >> operation;if (operation == 'P')cin >> stack[++tail];else if (operation == 'O'){if (tail == -1)tail = -1;elsetail--;}else if (operation == 'A')  //查询{if (tail >= 0)cout << stack[tail] << endl;elsecout << "E" << endl;}}cout << endl;}system("pause");return 0;}