c++ 简单计算器

3

1 2 3

+ +

#pragma warning(disable : 4996)
#define _CRT_SECURE_NO_WARNINGS 
#include
#include
#include
using namespace std;
int main() {
	stackst1;
	stackst2;
	char s;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		double n1;
		cin >> n1;
		st1.push(n1);
	}
	for (int i = 0; i < n - 1; i++) {
		cin >> s;
		st2.push(s);
	}
	int flag = 0;//运行成功，不遇到除数为0.
	while (!st2.empty()) {
		int n1= st1.top(); st1.pop();
		int n2= st1.top(); st1.pop();
		char ch = st2.top();
		st2.pop();
		if (ch == '-') {
			int sum = -n1+ n2;
			st1.push(sum);
		}
		else if (ch == '*') {
			int sum = n1* n2;
			st1.push(sum);
		}
		else if (ch == '+') {
			int  sum = n1+ n2;
			st1.push(sum);
		}
		else if (ch ==