Question

I’m trying to figure out how classes work, but I’m having a bit of trouble

main.cpp

#include <stdio.h>
#include "Student.h"
#include <stdlib.h>

void main()
{
Student students;

students.Print();

system("pause");

}

Student.h

#pragma once
#include <string.h>
#include <iostream>
using namespace std;

class Student
{
public:
    Student(void);
    ~Student(void);
    void Print(void);
private:
    int IDone;
    int IDtwo;
    string studentOne;
    string studentTwo;
};

Student.cpp

#include "Student.h"

Student::Student(void)
{
    studentOne = "John Doe";
    studentTwo = "Jane Doe";
    IDone = 227768;
    IDtwo = 227769;
}

Student::~Student(void)
{
}
void Student::Print(void)
{
    printf("Student name: %s\n", studentOne);
    printf("Student ID: %d\n", IDone);
    printf("Student name: %s\n", studentTwo);
    printf("Student ID: %d\n", IDtwo);

}

When this runs I get:

    Student name: <null>
    Student ID: 227768
    Student name: <null>
    Student ID: 227769

Later I want to be able to change the names and IDs. Also, it is possible to have these member in a type of array so I could print it by going student[0] and student[1]?

Answer 1

Read a reference about std::string and you will find a method named c_str that is used to get a C-style character pointer usable in e.g. printf.

Or just start using std::cout instead:

void Student::Print(void)
{
    std::cout << "Student name: " << studentOne << '\n';
    std::cout << "Student ID: " << IDone << '\n';
    std::cout << "Student name: " << studentTwo << '\n';
    std::cout << "Student ID: " << IDtwo << '\n';
}