【W.02 字符与字符串初步】计算器练习 答案

#include<iostream>
#include<cstring>
using namespace std;
int main(){
	string s;
	cin>>s;
	int a=0,b=0,flag=0;
	char op;
	for(int i=0;i<s.size();i++){
		if(s[i]=='+'||s[i]=='-'||s[i]=='*'||s[i]=='/'){
			op=s[i];
			flag=1;
		}else if(flag==0){
			a=a*10;
			a=a+s[i]-'0';
		}else{
			b=b*10;
			b=b+s[i]-'0';
		}
	}
	if(op=='/'&&b==0){
		cout<<"Divisor cannot be zero";
	}else{
		cout<<a<<" "<<op<<" "<<b<<" = ";
		if(op=='+')cout<<a+b;
		else if(op=='-')cout<<a-b;
		else if(op=='*')cout<<a*b;
		else cout<<a*1.0/b; 
	}
	
}