按值传递字符串：

#include 
#include 

void modifyString(std::string str) {
    str = "Modified";
    std::cout << "Inside modifyString function: " << str << std::endl;
}

int main() {
    std::string str = "Original";
    modifyString(str);
    std::cout << "After modifyString function: " << str << std::endl;
    return 0;
}

按引用传递字符串：

#include 
#include 

void modifyString(std::string& str) {
    str = "Modified";
    std::cout << "Inside modifyString function: " << str << std::endl;
}

int main() {
    std::string str = "Original";
    modifyString(str);
    std::cout << "After modifyString function: " << str << std::endl;
    return 0;
}

按 rvalue 传递字符串（使用 std::move）：

#include 
#include 

void modifyString(std::string&& str) {
    str = "Modified";
    std::cout << "Inside modifyString function: " << str << std::endl;
}

int main() {
    std::string str = "Original";
    modifyString(std::move(str));
    std::cout << "After modifyString function: " << str << std::endl;
    return 0;
}