简易后缀表达式计算器

有人能帮忙看一下有没有错吗（支持小括号、+-*/） 或者告诉我什么算式计算结果错误也行。

应为代码长，不要放在洛谷在线IDE里面跑（卡评测机），编译大约需要10秒左右（悲

#include<bits/stdc++.h>
using namespace std;
map<char, int> mp;

int res(string s){
	stack <int> a;
	int len = s.length();
	//cout << s << endl;
	//return 0;
    cout << "开始计算后缀表达式" << endl;
	for(int i = 0;i < len;i++){
		if(s[i] == '.'){
			continue;
		}else if(s[i] == '+'){
			int y = a.top();
			a.pop();
			int x = a.top();
			a.pop();
			a.push(x+y);
		}else if(s[i] == '-'){
			int y = a.top();
			a.pop();
			int x = a.top();
			a.pop();
			a.push(x-y);
		}else if(s[i] == '*'){
			int y = a.top();
			a.pop();
			int x = a.top();
			a.pop();
			a.push(x*y);
		}else if(s[i] == '/'){
			int y = a.top();
			a.pop();
			int x = a.top();
			a.pop();
			a.push(x/y);
		}else{
			string num = "";
			while(s[i] != '.'){
				num += s[i];
				i++;
			}
            cout << "数字处理 字符型数字：" <<num << "，数字型数字：" ;
			int numlen = num.length();
			int j = numlen-1;
			int sum = 0;
			for(int i = 0;i < numlen;i++,j--){
				sum += (num[i]-'0')*pow(10,j);
			}
			cout << sum  << "。\n";
			a.push(sum);
		}
	}
	return a.top();
} 
string make(string s){
	string res = "",x = "";
	stack <char> a;
	int len = s.length();
	cout << "开始制作表达式" << endl;
	for(int i = 0;i < len;i++){
		cout << s[i] << endl;
		if(s[i] <= '9' && s[i] >= '0'){
			x += s[i];
		}else{
			res += '.'+x + '.';
			x = "";
			if(s[i] == '+' || s[i] == '-'){
				if(s[i] == '+'){
					if(a.empty()){
						a.push(s[i]);
					}else if(a.top() == '('){
						a.push(s[i]);
					}else{
						while(1){
							if(a.empty()){
								break;
							}else if(mp[a.top()] > 1){
								res += a.top();
								a.pop();
							}else{
								break;
							}
						}
					}
				}
				if(s[i] == '-'){
					if(a.empty()){
						a.push(s[i]);
					}else if(a.top() == '('){
						a.push(s[i]);
					}else{
						while(1){
							if(a.empty()){
								break;
							}else if(mp[a.top()] > 1){
								res += a.top();
								a.pop();
							}else{
								break;
							}
						}
					}
				}
			}else if(s[i] == '*' || s[i] == '/'){
				if(s[i] == '*'){
					if(a.empty()){
						a.push(s[i]);
					}else if(a.top() == '(' || a.top() == '+' || a.top() == '-'){
						a.push(s[i]);
					}else{
						res += s[i];
					}
				}
				if(s[i] == '/'){
					if(a.empty()){
						a.push(s[i]);
					}else if(a.top() == '(' || a.top() == '+' || a.top() == '-'){
						a.push(s[i]);
					}else{
						res += s[i];
					}
				}
			}else if(s[i] == '('){
				a.push(s[i]);			
			}else{
				while(a.top() != '('){
					res += a.top();
					a.pop();
				}
				a.pop();
			}
		}
		
	}
	res += '.'+x+'.';
	while(!a.empty()){
		res += a.top();
		a.pop();
	}
	return res;
}
int main(){
	cout << "开始" << endl;
	mp['+'] = 1;
	mp['-'] = 1;
	mp['*'] = 2;
	mp['/'] = 2;
	mp['('] = 0;	
	string a,b;
	cout << "赋值完成" << endl;
	cin >> a;
	b = make(a);
	cout << "后缀表达式制作完成，表达式为" << b << endl;
	cout << res(b) << endl;
	cout << "程序结束" << endl;
	return 0;
}