Kotlin Program to Swap Two Numbers

In this article, we will understand how to how to swap two numbers in Kotlin. This is done using a temporary variable.

Below is a demonstration of the same

Suppose our input is

val1 : 45
val2 : 60

The desired output would be

val1 : 60
val2 : 45

Algorithm

• Step 1 ? Start

• Step 2 ? Declare three integers: val1, val2 and tempVal

• Step 3 ? Define the values

• Step 4 ? Assign val1 to temporary variable

• Step 5 ? Assign val2 to val1

• Step 6 ? Assign temporary tempVal variable to val2

• Step 7 ? Display the two values

• Step 8 ? Stop

Example 1

In this example, we will swap two numbers using a temporary variable ?

<div class="execute"></div><div class="code-mirror  language-kotlin" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">fun</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">var</span> val1 <span class="token operator">=</span> <span class="token number">45</span>
   <span class="token keyword">var</span> val2 <span class="token operator">=</span> <span class="token number">60</span>

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The first value is defined as: <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is defined as: <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>

   <span class="token keyword">val</span> tempVal <span class="token operator">=</span> val1
   val1 <span class="token operator">=</span> val2
   val2 <span class="token operator">=</span> tempVal

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"\nAfter swapping"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The first value is = <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is = <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

The first value is defined as: 45
The second value is defined as: 60

After swapping
The first value is = 60
The second value is = 45

Example 2

In this example, we will swap two numbers without using a temporary variable ?

<div class="execute"></div><div class="code-mirror  language-kotlin" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">fun</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">var</span> val1 <span class="token operator">=</span> <span class="token number">25</span>
   <span class="token keyword">var</span> val2 <span class="token operator">=</span> <span class="token number">55</span>
   
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The first value is defined as: <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is defined as: <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>

   val1 <span class="token operator">=</span> val1 <span class="token operator">+</span> val2
   val2 <span class="token operator">=</span> val1 <span class="token operator">-</span> val2
   val1 <span class="token operator">=</span> val1 <span class="token operator">-</span> val2

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"\nAfter swapping"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"\nThe first value is = <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is = <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

The first value is defined as: 25
The second value is defined as: 55

After swapping
The first value is = 55
The second value is = 25

Example 3

We can also swap two numbers using the following code

<div class="execute"></div><div class="code-mirror  language-kotlin" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">fun</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">var</span> val1 <span class="token operator">=</span> <span class="token number">20</span>
   <span class="token keyword">var</span> val2 <span class="token operator">=</span> <span class="token number">10</span>

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The first value is defined as: <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is defined as: <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>

   val1 <span class="token operator">=</span> val1 <span class="token operator">-</span> val2
   val2 <span class="token operator">=</span> val1 <span class="token operator">+</span> val2
   val1 <span class="token operator">=</span> val2 <span class="token operator">-</span> val1

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"\nAfter swapping"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"\nThe first value is = <span class="token interpolation variable">$val1</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The second value is = <span class="token interpolation variable">$val2</span>"</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

The first value is defined as: 20
The second value is defined as: 10

After swapping

The first value is = 10
The second value is = 20