error in main: java.lang.NullPointerException

Question

i'm new to java programming. i have a problem with my code, i keep getting this error no matter what i try. so i have a main class and a Pair class (which has 2 member variables (private int a, private int b) the Pair class has it's setters and getters. i have been trying to create an array of Pair and initialize it, yet i keep getting this error: Exception in thread "main" java.lang.NullPointerException

package com.company;

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    System.out.println("enter a puis b");
    int x=0;
    int y=0;

    Pair p []= new Pair[6];

    for (int i = 0; i < p.length; i++) {
        x = sc.nextInt();
        y = sc.nextInt();
        p[i].setA(x);
        p[i].setB(y);
    }
    for (int i = 0; i < p.length; i++) {
        System.out.println(p[i]);
    }


}
}

heres the Pair class:

public  class Pair {
private int a = 0;
private int b = 0;

public Pair() {
    this.b = 0;
    this.a = 0;
}

public int getA() {
    return a;
}

public void setA(int x) {
    a = x;
}

public int getB() {
    return b;
}

i need some help. thank you for your time :)

Answer 1

You are not initializing every member of your array, you need to use:

p[0] = new Pair(); And so on...

You can do this inside your for loop:

for (int i = 0; i < p.length; i++) {
    p[i] = new Pair();
    ... // more code
}