加减乘除阶乘计算器c++

在C++中编写一个加减乘除以及阶乘的计算器，你可以创建一个简单的控制台应用程序，利用函数来分别处理这几种运算。下面是一个基础的示例：

#include <iostream>
using namespace std;

// 计算整数相加
int add(int a, int b) {
    return a + b;
}

// 计算整数相减
int subtract(int a, int b) {
    return a - b;
}

// 计算整数相乘
int multiply(int a, int b) {
    return a * b;
}

// 计算整数相除（需要处理除数为0的情况）
double divide(int a, int b) {
    if (b == 0) {
        cout << "Error: Division by zero is not allowed." << endl;
        return 0;
    }
    return static_cast<double>(a) / b;
}

// 计算阶乘
int factorial(int n) {
    if (n == 0 || n == 1) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}

int main() {
    int num1, num2;
    char operation;

    cout << "Enter the first number: ";
    cin >> num1;
    cout << "Enter the second number: ";
    cin >> num2;
    cout << "Choose an operation (+, -, *, /, ! for factorial): ";
    cin >> operation;

    switch (operation) {
        case '+':
            cout << "Result: " << add(num1, num2) << endl;
            break;
        case '-':
            cout << "Result: " << subtract(num1, num2) << endl;
            break;
        case '*':
            cout << "Result: " << multiply(num1, num2) << endl;
            break;
        case '/':
            cout << "Result: " << divide(num1, num2) << endl;
            break;
        case '!':
            cout << "Factorial of " << num1 << ": " << factorial(num1) << endl;
            break;
        default:
            cout << "Invalid operation!" << endl;
    }

    return 0;
}