How should we add function inside a structure?

Question

#include <iostream>

using namespace std;

struct teacher
{
    int id;
    char name[50];
    int salary;

    void input(teacher a)
    {
        cout << "Enter Name : ";
        cin >> a.name;
        cout << "Enter ID : ";
        cin >> a.id;
        cout << "Enter Salary : ";
        cin >> a.salary;
    }

    void output(teacher b)
    {
        cout << "Your Name Is : " << b.name << endl;
        cout << "Your ID Is : " << b.id << endl;
        cout << "Your Salary Is : " << b.salary;
    }
};

int main()
{
    teacher t;
    t.input(t);
    t.output(t);

    return 0;
}

Is there any problem? The output is random numbers, don't know what is it. I tried writing the output function separately, but still same results.

Unrelated: drop `using namespace std;`, use `std::cout` instead. Replace `char` arrays by `std::string`. Don't use `std::endl` instead use `"\n"`, don't pass `teacher` to `input/output`, use `class` instead of `struct`. — Micha Wiedenmann, Mar 02 '20 at 12:49
Does this answer your question? [What's the difference between passing by reference vs. passing by value?](https://stackoverflow.com/questions/373419/whats-the-difference-between-passing-by-reference-vs-passing-by-value) — Borgleader, Mar 02 '20 at 12:49
Just as a side note: [Why is "using namespace std;" considered bad practice?](https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice) — Andreas Wenzel, Mar 02 '20 at 12:51
I'm currently learning oop , so before using class , I tried doing it with structure. — Qasim Ahmed, Mar 02 '20 at 12:54
`class` and `struct` are functionally equivalent in C++, the only difference is their default visibility (private for `class`, public for `struct`). You can use either/or. — NotAProgrammer, Mar 02 '20 at 12:56

score 0 · Answer 1 · answered Mar 02 '20 at 12:48

This seems like a weird design, why don't your class methods directly operate on this?

struct teacher
{
    int id;
    std::string name;
    int salary;

    void input()
    {
        cout << "Enter Name : ";
        cin >> name;
        cout << "Enter ID : ";
        cin >> id;
        cout << "Enter Salary : ";
        cin >> salary;
    }

    void output() const
    {
        cout << "Your Name Is : " << name << endl;
        cout << "Your ID Is : " << id << endl;
        cout << "Your Salary Is : " << salary;
    }
};

Then main would look like

int main()
{
    teacher t;
    t.input();
    t.output();

    return 0;
}

Also I'd prefer to use std::string instead of char[] when possible.

yes, using char always gave me errors, I'll try using std::string from now — Qasim Ahmed, Mar 02 '20 at 12:56

score 0 · Answer 2 · answered Mar 02 '20 at 12:48

0

In input() you modify parameter a which goes out of scope when it reaches the end of the function.

Instead you should modify the class members variables themselves.

void input()
{
    cout << "Enter Name : ";
    cin >> name;
    cout << "Enter ID : ";
    cin >> id;
    cout << "Enter Salary : ";
    cin >> salary;
}

answered Mar 02 '20 at 12:48

acraig5075

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@QasimAhmed The way to acknowledge help on SO is to vote the answer up. – acraig5075 Mar 05 '20 at 06:10

How should we add function inside a structure?

2 Answers2