注意:
1、每一个case后面要有break
2、/运算的时候注意分母不能为0
cpp
int a, b;
char c;
cin>>a>>b>>c;
switch (c)
{
case '+':
cout << a << '+' << b << '=' << a + b << endl;
break;
case '-':
cout << a << '-' << b << '=' << a - b << endl;
break;
case '*':
cout << a << '*' << b << '=' << a * b << endl;
break;
case '/':
if (b == 0)
{
cout << "分母不能为0" << endl;
}else
cout << a << '/' << b << '=' << a /b << endl;
break;
default:
cout << "表达式错误" << endl;
}