Java puzzle 26: Invoking a method within a method

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This code demonstrates invoking a method within another method.

Java puzzle 26: Invoking a method within a method

Level: Normal

What is the output of this program and why?

public class MyClass
{
  int x = 2;
  int y = 5;
  
  void myMethod(int x, int y)
  {
    this.x += x;
    this.y += y;
  }
  void print()
  {
    myMethod(3, 1);
    System.out.print("x" + x + "y" + y);
  }
  public static void main(String[] args)
  {
    new MyClass().print();
  }
}

Author: Sar Maroof

Answer explanation

The statement myMethod(3, 1); invokes the method myMethod. The statement this.x += x; adds the value of the parameter x to the value of the instance variable x. So, x = the initial value of x + 3 = 2 + 3 = 5.
The statement this.y += y; adds the value of the parameter y to the value of the instance variable y. So, y = its initial value + 1, y = 5 + 1 = 6.
So, the statement System.out.print(“x” + x + “y” + y); writes x5y6 to the standard output.

The correct answer is: x5y6

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Sar Maroof is graduated from HBO Amsterdam "higher professional education". He is a professional computer programming teacher, gives master classes and publishes technical articles. His experience with developing software started from 2001 and he has worked as a software developer for several big as well as small companies and later as a freelancer. He is the author of Java quizmaster and Build a Java application in 7 days.