如何使用 char* 从用户那里获取数据，然后在 C++ 中执行输入数据的深度复制？

Question

Take data from user in runtime from char*

Answer 1

You should be using std::string , which performs all the data lifetime management and deep copy for you.

In turn, that makes the Student class's destructor, default constructor, copy constructor all just do the right thing . Also the assignment operator will just do the right thing , but that's not exercised in the main routine.

In the code, I used = default on the destructor, default constructor, and copy constructor to highlight that the default compiler generated routines are good.

A couple of improvements would be for Getinfo() to be Getinfo(istream& in, ostream& out) , and for show() to be show(ostream& out) .

#include <iostream>
#include <stdexcept>
#include <string>

using std::cin;
using std::cout;
using std::istream;
using std::runtime_error;
using std::stof;
using std::stoi;
using std::string;

static auto get_string(istream&) -> string;
static auto get_int(istream&) -> int;
static auto get_float(istream&) -> float;

class Student final {
    string name;
    int age = 0;
    float gpa = 0.0f;
public:
    ~Student() = default;
    Student() = default;
    Student(string n, int a, float g) : name{move(n)}, age(a), gpa(g) { }
    Student(Student const&) = default;

    void Getinfo() {
        cout << "Enter your name: ";
        name = get_string(cin);
        cout << "Enter your age: ";
        age = get_int(cin);
        cout << "Enter your GPA: ";
        gpa = get_float(cin);
    }

    void show() {
        cout << "Name: " << name << "\n"
            << "Age: " << age << "\n"
            << "GPA: " << gpa << "\n";
    }
};

int main() {
    Student s1;
    s1.Getinfo();
    s1.show();
    Student s2 = s1;
    s2.show();
    Student s3(s2);
    s3.show();
}

auto get_string(istream& in) -> string {
    string line;

    if (getline(in, line)) {
        return line;
    }

    throw runtime_error("get_string");
}

auto get_int(istream& in) -> int {
    string line;

    if (getline(in, line)) {
        return stoi(line);
    }

    throw runtime_error("get_int");
}

auto get_float(istream& in) -> float {
    string line;

    if (getline(in, line)) {
        return stof(line);
    }

    throw runtime_error("get_float");
}