如何在c++中从switch语句返回不同类型的变量

#include <iostream>
#include <string>

struct Result {
    enum Type { INT, FLOAT, STRING };
    Type type;
    union {
        int intValue;
        float floatValue;
        std::string stringValue;
    };
};

Result getValue(int choice) {
    Result result;
    switch (choice) {
        case 1:
            result.type = Result::INT;
            result.intValue = 42;
            break;
        case 2:
            result.type = Result::FLOAT;
            result.floatValue = 3.14f;
            break;
        case 3:
            result.type = Result::STRING;
            result.stringValue = "Hello, world!";
            break;
        default:
            // Handle invalid choice
            break;
    }
    return result;
}

int main() {
    int choice;
    std::cout << "Enter choice (1, 2, or 3): ";
    std::cin >> choice;

    Result result = getValue(choice);

    switch (result.type) {
        case Result::INT:
            std::cout << "Returned int value: " << result.intValue << std::endl;
            break;
        case Result::FLOAT:
            std::cout << "Returned float value: " << result.floatValue << std::endl;
            break;
        case Result::STRING:
            std::cout << "Returned string value: " << result.stringValue << std::endl;
            break;
        default:
            // Handle invalid result
            break;
    }

    return 0;
}