#C++语言编写的简单计算器
#include<iostream> //包含输入输出头文件
#include<cmath>
using namespace std; //指定名字空间
int main() //主函数
{
double num1,num2;
char op; //声明字符变量,存放操作符
double result; //声明变量,存放计算机结果
char caption1[20]="Erro,Divided by 0!";
char caption2[20]="Invalid opereator!";
cout<<"Please input the expression:";
cin>>num1>>op>>num2;
switch(op)
{
case'+': result=num1+num2;
cout<<num1<<op<<num2<<"="<<result<<endl;
break;
case'-': result=num1-num2;
cout<<num1<<op<<num2<<"="<<result<<endl;
break;
case'*': result=num1*num2;
cout<<num1<<op<<num2<<"="<<result<<endl;
break;
case'/':
if(fabs(num2)<1.0e-8) //除数为0,判断变量num2的绝对值是否小于1*10的负8次方
{
cout<<caption1<<endl;
}
else //除数不为0
{
result=num1/num2;
cout<<num1<<op<<num2<<"="<<result<<endl;
}
break;
default: //以上情况都不是
cout<<caption2<<endl;
}
return 0;
}