# Scala program to swap two numbers

Scala | Swapping two numbers: Here, we are going to learn how to swap two numbers in Scala programming language?
Submitted by Shivang Yadav, on April 21, 2020 [Last updated : March 09, 2023]

## Scala – Swap Two Numbers

Given two numbers, we have to swap them. There are two ways to swap two numbers. They are,

1. Using third variable
2. Without using third variable

Example:

```    Input:
a = 10
b = 20

Output:
a = 20
b = 10
```

## 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
```

### Scala code to swap two number using third variable

```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
```

### Scala code to swap two number without using third variable

```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
```