使用`switch`语句接受变量参数类型的模板化函数中的回调函数

#include <iostream>
#include <functional>

template <typename T>
void process(T value, std::function<void(T)> callback) {
    switch (value) {
        case 1:
            callback(1);
            break;
        case 2:
            callback(2);
            break;
        default:
            callback(0);
            break;
    }
}

int main() {
    auto printValue = [](int value) {
        std::cout << "Value is: " << value << std::endl;
    };

    process(1, printValue);
    process(2, printValue);
    process(3, printValue);

    return 0;
}

template <>
void process<std::string>(std::string value, std::function<void(std::string)> callback) {
    if (value == "hello") {
        callback("hello");
    } else {
        callback("unknown");
    }
}

auto printString = [](std::string value) {
    std::cout << "String is: " << value << std::endl;
};

process<std::string>("hello", printString);