c++分支如何实现条件判断

在C++中，可以使用if-else语句、switch语句或者三元运算符（条件运算符）来实现条件判断。下面是这三种方法的示例：

1. if-else语句：

#include <iostream>
using namespace std;

int main() {
    int number = 10;

    if (number > 0) {
        cout << "The number is positive." << endl;
    } else if (number < 0) {
        cout << "The number is negative." << endl;
    } else {
        cout << "The number is zero." << endl;
    }

    return 0;
}

2. switch语句：

#include <iostream>
using namespace std;

int main() {
    int day = 3;

    switch (day) {
        case 1:
            cout << "Monday" << endl;
            break;
        case 2:
            cout << "Tuesday" << endl;
            break;
        case 3:
            cout << "Wednesday" << endl;
            break;
        case 4:
            cout << "Thursday" << endl;
            break;
        case 5:
            cout << "Friday" << endl;
            break;
        case 6:
            cout << "Saturday" << endl;
            break;
        case 7:
            cout << "Sunday" << endl;
            break;
        default:
            cout << "Invalid day" << endl;
    }

    return 0;
}

3. 三元运算符（条件运算符）：

#include <iostream>
using namespace std;

int main() {
    int number = 10;

    string result = (number > 0) ? "The number is positive." : (number < 0) ? "The number is negative." : "The number is zero.";

    cout << result << endl;

    return 0;
}

以上三种方法都可以实现条件判断，根据具体需求和场景选择合适的方法。