Thread: Write a Java program to swap two variables.

Not sure where to post this question since its my first time on this forum. But I wanted to see if my code for swapping two variables is correct or if there is another way:

I did mines two ways:

First way (with known variables)
Input:

class RicMain  
 
{ 
 
    public static void main(String args[])  
 
    { 
 
        int x = 10; 
 
        int y = 20; 
 
 
 
        System.out.println("Before swapping"); 
 
        System.out.println("x = " + x); 
 
        System.out.println("y = " + y); 
 
 
 
        System.out.println("After swapping"); 
 
        System.out.println("x = " + y); 
 
        System.out.println("y = " + x); 
 
    }     
 
}

Second way(where the user has to input two variables)

import java.util.Scanner; 
 
 
 
class RicMain  
 
{ 
 
    public static void main(String args[])  
 
    { 
 
        Scanner swap = new Scanner(System.in); 
 
        int x, y; 
 
 
 
        System.out.println("Enter num for x: "); 
 
        x = swap.nextInt(); 
 
        System.out.println("Enter num for y: "); 
 
        y = swap.nextInt(); 
 
 
 
        System.out.println("Before swap"); 
 
        System.out.println("x = " + x); 
 
        System.out.println("y = " + y); 
 
 
 
        System.out.println("After swap"); 
 
        System.out.println("x = " + y); 
 
        System.out.println("y = " + x); 
 
    }     
 
}

Are these good?

Can you define what you mean by "swap variables"?
Normally I understand swap to mean that the contents of the variables are swapped. For example:
Before a swap:
x=10
y=20
after the swap
x=20
y=10

Your code does not swap the contents of the variables. It swaps the order that their contents are printed.

What if you have an egg in each hand and you want to swap the eggs? How would you do it? A hand can only hold one egg at a time. There is another person there that could help.

you put one egg(the one in your right hand) on the counter,

Yes that is how I would do it. In programming, "on the counter" would mean using another variable (often named temp) to hold the value during the swap.

So now I rewrote my code. How does it look?

Input:

class RicMain  
{ 
	public static void main(String args[])  
    { 
        int x = 10; 
        int y = 20; 
        int z; //z is the "holding" variable
 
        System.out.println("Before swapping"); 
        System.out.println("x = " + x); 
        System.out.println("y = " + y); 
 
        z = x; //z holds 10
        x = y; // y now has 20
        y = z; // y now has 10
        System.out.println("After swapping");
        System.out.println("x = " + x);
        System.out.println("y = " + y);
    }     
}

Do you get the expected output?
One change: use the name temp instead of z so anyone looking at the code understands what the variable is used for.
x,y,z look like 3 variables that are meant to hold values.

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