Printing out the wrong value - c++

Question

I'm trying to write a program that takes the grades and prints out the following:
ID:123 NAME:John GRADE:78
but instead I'm getting:
ID:-842150451 NAME: GRADE: 78
Can you guys help me and give me some extra tips to make my code cleaner since I'm fairly new to C++.
Student.h
#ifndef STUDENT_H
#define STUDENT_H
#include <iostream>
#include <string>
using namespace std;
class Student {
public:
Student(int num, string text);
int getID();
void setExamGrade(int a, int b);
int getOverallGrade();
void display();
string getName();
string name;
int id;
int exams[3];
int sum;
int average;
};
#endif
Student.cpp
#ifndef STUDENT_CPP
#define STUDENT_CPP
#include "Student.h"
#include <iostream>
#include <string>
using namespace std;
Student::Student(int num, string text)
{
num = id;
text = name;
exams[0, 1, 2] = 0;
}
int Student::getID() {
return id;
}
string Student::getName() {
return name;
}
void Student::setExamGrade(int a, int b) {
exams[a] = b;
}
int Student::getOverallGrade() {
sum = exams[0] + exams[1] + exams[2];
average = sum / 3;
return average;
}
void Student::display() {
cout << "ID: " << getID();
cout << " NAME: " << getName();
cout << " GRADE: " << getOverallGrade() << endl;
}
#endif
gradebook.cpp
#ifndef GRADEBOOK_CPP
#define GRADEBOOK_CPP
#include "Student.h"
#include <iostream>
using namespace std;
int main() {
Student *s = new Student(123, "John");
s->setExamGrade(0, 80);
s->setExamGrade(1, 60);
s->setExamGrade(2, 95);
s->display();
delete s;
return 0;
}
#endif

Answer 1

You never assign to id in the constructor, hence it's uninitialized and you will have undefined behavior when you print it.
Change
num = id;
to
id = num;
Same with the name.
Also, the statement
exams[0, 1, 2] = 0;
doesn't do what you expect it to do, it only initializes exams[2] to sero, and leaves the rest uninitialized. The expression 0, 1, 2 uses the comma operator.
Either assign to all members of the array separately, or use a constructor member initializer list (which I recommend for all the initialization).