我正在尝试制作一个程序，它可以根据用户在C++中的选择来运行不同的函数

#include <iostream>

void functionA() {
    std::cout << "This is function A." << std::endl;
}

void functionB() {
    std::cout << "This is function B." << std::endl;
}

void functionC() {
    std::cout << "This is function C." << std::endl;
}

int main() {
    int userChoice;
    std::cout << "Please enter your choice (1, 2, or 3): ";
    std::cin >> userChoice;

    if (userChoice == 1) {
        functionA();
    } else if (userChoice == 2) {
        functionB();
    } else if (userChoice == 3) {
        functionC();
    } else {
        std::cout << "Invalid choice." << std::endl;
    }

    return 0;
}