Scala program to swap two numbers

1) Swapping two numbers using third variable

To swap two values, there is a simple approach is using a temporary variable that stores the element for swapping.

Algorithm:

Let, variable a contains first value, variable b contains second value and temp is the temporary variable.

    Step 1: temp = a
    Step 2: a = b
    Step 3: b = temp 

Program:

object myObject {
    def main(args: Array[String]) {
        var a = 10
        var b = 20
        
        println("Values before swapping:\t a= " + a + ", b= " + b)
        
        // swapping
        var temp = a
        a = b
        b = temp
        
        println("Values after swapping:\t a= " + a + ", b= " + b)
        
    }
}

Output

Values before swapping:	 a= 10, b= 20
Values after swapping:	 a= 20, b= 10

2) Swapping two numbers without using third variable

We can also swap two numbers without using the third variable. This method saves computation space hence is more effective.

Let, variable a contains first value, variable b contains second value.

    Step 1: a = a + b
    Step 2: a = a - b
    Step 3: b = a - b 

Program:

object myObject {
    def main(args: Array[String]) {
        var a = 10
        var b = 20
        
        println("Values before swapping:\t a= " + a + ", b= " + b)
        
        // swapping
        a = a + b
        b = a - b
        a = a - b
        
        println("Values after swapping:\t a= " + a + ", b= " + b)
        
    }
}

Output

Values before swapping:	 a= 10, b= 20
Values after swapping:	 a= 20, b= 10