2 1.2 -

0.8

复制代码到粘帖板
#include<iostream>
using namespace std;
int main()
{
	float a, b, sum;
	char c;
	cin >> a >> b;
	cin>>c;
	
	//else if (c != '+' && c != '-' &&c != '*' && c != '/')
		//cout << "Invalid operator!";
	//方法一

		switch (c)
		{
		case '+':sum = a + b; cout << sum; break;
		case'-':sum = a - b; cout << sum; break;
		case'*':sum = a * b; cout << sum; break;
		case'/':if (b != 0) { cout << a / b; break; }
			else cout << "Divided by zero!"; break;
		default:cout << "Invalid operator!";//方法二

		}
		
}