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I know constructor is a special member of class use to initialize data member..But why we actually need constructor can somebody tell me.

Omkar Doke
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    _"...to initialize data member"_ - this is exactly why constructor is used. It initializes the newly created instance. – Yousaf Nov 29 '21 at 05:41
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    Does this answer your question? [Purpose of a constructor in Java?](https://stackoverflow.com/questions/19941825/purpose-of-a-constructor-in-java) – zysaaa Nov 29 '21 at 05:47
  • Because we need to. An object is created using a constructor by definition. This is not Java specific, this is about class based object orientated development. Some languages though, like the infamous _ECMAScript_ aka "JavaScript" copy/link prototypes instead of instantiating classes. – Amadán Nov 29 '21 at 08:05

1 Answers1

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We can use constructor to set it's fields.

public class FutilePoint {
    
    private double x, y, size;
    private int color;
    
    public FutilePoint(double pos_x, double pos_y, double size, int color_RGB) {
        this.x = pos_x;
        this.y = pos_y;
        this.size = size;
        this.color = color_RGB;
    }

    public FutilePoint(pos_x, pos_y) {
        this.x = pos_x;
        this.y = pos.y;
        this.size = 4;
        this.color = 0x000000;
    }
}

Then we can create many different objects.

#import src.FutilePoint;

//somewhere in a random class...

public void doMeaninglessStuff() {
    for(int i = 1; i <= 99999999; i++) {
        for(int j = 1; j <= 99999999; j++) {
            new FutilePoint(i, j);
        }
    }
    new Point(0, 0, 128, 0xFFFF3A);
}

You can also use it's methods in the constructor.

George Glebov
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