小朋友学C++（24）：实现简易计算器

港控/mmm° 2022-04-10 20:40 228阅读 0赞

# 一、需求 #

编写一个简易计算器，能实现最基本的加减乘除四则运算。

# 二、代码实现 #

#include <iostream>
    using namespace std;
    
    int main()
    {
    	double num1,num2;
    	char op;	// 运算符号 
    	char flag;	// 是否继续运算，'Y'或'y'表示是，'N'或'n'表示否
    	
    	while(true)
    	{
    		cout << "Enter first number:" << endl;
    		cin >> num1;
    		cout << "Enter second number:" << endl;
    		cin >> num2;
    		
    		while(true)
    		{
    			cout <<"Please input operator(+,-,*,/):" << endl;
    			cin >> op;
    			
    			if('+' == op)
    			{
    				cout << num1 << " + " << num2 << " = " << num1 + num2 << endl; 
    				break;
    			}
    			else if('-' == op)
    			{
    				cout << num1 << " - " << num2 << " = " << num1 - num2 << endl; 
    				break;
    			}
    			else if('*' == op)
    			{
    				cout << num1 << " * " << num2 << " = " << num1 * num2 << endl; 
    				break;
    			}
    			else if('/' == op)
    			{
    				if(0 == num2)
    				{
    					cout << "Number can't be divided by 0" << endl;
    					break;
    				}
    				cout << num1 << " / " << num2 << " = " << num1 / num2 <<endl; 
    				break;
    			}
    			else
    			{
    				cout << "Invalid input" << endl;
    				continue;
    			}
    		}
    		
    		cout << "Do you want to continue the program?(Y/N)" << endl;
    		cin >> flag;
    		
    		if('N' == flag || 'n' == flag)
    		{
    			break;
    		}
    		else if('Y' == flag || 'y' == flag)
    		{
    			continue;
    		}
    	}
    	
    	return 0;
    }

运行结果：

3
    Enter second number:
    5
    Please input operator(+,-,*,/):
    +
    3 + 5 = 8
    Do you want to continue the program?(Y/N)
    y
    Enter first number:
    4
    Enter second number:
    5
    Please input operator(+,-,*,/):
    /
    4 / 5 = 0.8
    Do you want to continue the program?(Y/N)
    y
    Enter first number:
    1
    Enter second number:
    0
    Please input operator(+,-,*,/):
    /
    Number can't be divided by 0
    Do you want to continue the program?(Y/N)
    n
    
    --------------------------------
    Process exited after 30.04 seconds with return value 0
    请按任意键继续. . .

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