c++自定义函数简单计算器

在C++中，你可以创建一个简单的函数来实现一个计算器功能，比如加、减、乘、除操作。下面是一个基础示例，它包含一个`Calculator`类，其中定义了四个基本运算的方法：

#include <iostream>

class Calculator {
public:
    // 加法
    int add(int a, int b) { return a + b; }
    
    // 减法
    int subtract(int a, int b) { return a - b; }

    // 乘法
    int multiply(int a, int b) { return a * b; }

    // 除法（注意处理除数为0的情况）
    int divide(int a, int b) {
        if (b != 0) {
            return a / b;
        } else {
            std::cerr << "Error: Division by zero is not allowed.\n";
            return 0;
        }
    }
};

int main() {
    Calculator calc;

    int num1, num2;
    char operation;

    std::cout << "Enter first number: ";
    std::cin >> num1;
    std::cout << "Enter an operator (+, -, *, /): ";
    std::cin >> operation;
    std::cout << "Enter second number: ";
    std::cin >> num2;

    switch(operation) {
        case '+':
            std::cout << "Result: " << calc.add(num1, num2) << "\n";
            break;
        case '-':
            std::cout << "Result: " << calc.subtract(num1, num2) << "\n";
            break;
        case '*':
            std::cout << "Result: " << calc.multiply(num1, num2) << "\n";
            break;
        case '/':
            std::cout << "Result: " << calc.divide(num1, num2) << "\n";
            break;
        default:
            std::cerr << "Invalid operator. Please use +, -, *, or /\n";
    }

    return 0;
}