在引用函数 c++ 中使用的参数

Question

我很困惑我会在我的函数中放入什么样的变量：names。我在 C++ 书中做一个练习题，因为我正在学习 C++，并且现在在参考和指针上，并且找不到解决方案。

只是为了背景信息，问题问：

编写一个函数，提示用户输入他或她的名字和姓氏，作为两个单独的值。
此函数应通过传递给函数的附加指针（或引用）参数将这两个值返回给调用者。
尝试先使用指针，然后使用引用。

#include <iostream>
#include <string>
#include <istream>

using namespace std;

struct someStruct{
    string firstname;
    string lastname;
};

void names(someStruct &firstname, someStruct &lastname) {
    cout << "First Name: " << "\n";
    cin >> firstname.firstname;
    cout << "Last Name: " << "\n";
    cin >> lastname.lastname;
    // I was just curious is adding firstname to firstname would work... and     it did
    cout << lastname.lastname << ", " << firstname.firstname;
    cin.get();
}

int main() {
    names();
    // I don't know what to put here, above, as parameters
    cin.get();
}

Answer 1

你的代码没有意义，你为什么要传递someStruct 两次？

对于 reference 部分，您应该有类似的内容：

void names(someStruct &s) { // <<<< Pass struct once as a reference
    cout << "First Name: " << "\n";
    cin >> s.firstname;
    cout << "Last Name: " << "\n";
    cin >> s.lastname;
}

在main():

int main() {
    someStruct x; // <<<< Create an instance of someStruct
    names(x); // <<<< Pass it as parameter

    cout << "Input was: firstName = " << x.firstname 
         << ", lastName = " << x.lastname 
         << endl;
    cin.get();
}

---

对于 pointer 部分，你应该有类似的东西：

void names(someStruct *s) { // <<<< Pass struct once as a reference
    cout << "First Name: " << "\n";
    cin >> s->firstname;
         // ^^ Note the difference in dereferencing
    cout << "Last Name: " << "\n";
    cin >> s->lastname;
         // ^^ Note the difference in dereferencing
}

在main():

int main() {
    someStruct x; // <<<< Create an instance of someStruct
    names(&x); // <<<< Pass the address of x as parameter
       // ^ Note the addess-of operator here

    cout << "Input was: firstName = " << x.firstname 
         << ", lastName = " << x.lastname 
         << endl;
    cin.get();
}