Swift Program to Find the Largest Among Three Numbers

This tutorial will discuss how to write a Swift program to find the largest among three numbers.

Given three numbers now we have to find the largest among the given three numbers. So we will compare all three numbers with each other to find the largest number.

Below is a demonstration of the same ?

Suppose we enter the following input ?

39, 87, 12

Following is the desired output ?

Largest number is 87

Finding largest number using max() function

Swift provides an in-built method named as max() function. This function returns the maximum number among the given numbers.

Syntax

Following is the syntax of the Swift max() function ?

max(num1, num2, num3)

Algorithm

The algorithm is explained below ?

• Step 1 ? Declare three variables

• Step 2 ? read their values from the user.

• Step 3 ? Use the max() function to find the largest number among the three numbers.

• Step 4 ? Print the output.

Example

The following program shows how to find the largest among three numbers using the max() function.

<div class="code-mirror  language-swift" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">import</span> <span class="token class-name">Foundation</span>
<span class="token keyword">import</span> <span class="token class-name">Glibc</span>

<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Enter first number"</span></span><span class="token punctuation">)</span>
<span class="token keyword">var</span> num1 <span class="token operator">=</span> <span class="token class-name">Int</span><span class="token punctuation">(</span><span class="token function">readLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">!</span><span class="token punctuation">)</span><span class="token operator">!</span>
<span class="token function">print</span><span class="token punctuation">(</span>num1<span class="token punctuation">)</span>

<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Enter second number"</span></span><span class="token punctuation">)</span>
<span class="token keyword">var</span> num2 <span class="token operator">=</span> <span class="token class-name">Int</span><span class="token punctuation">(</span><span class="token function">readLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">!</span><span class="token punctuation">)</span><span class="token operator">!</span>
<span class="token function">print</span><span class="token punctuation">(</span>num2<span class="token punctuation">)</span>

<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Enter third number"</span></span><span class="token punctuation">)</span>
<span class="token keyword">var</span> num3 <span class="token operator">=</span> <span class="token class-name">Int</span><span class="token punctuation">(</span><span class="token function">readLine</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">!</span><span class="token punctuation">)</span><span class="token operator">!</span>
<span class="token function">print</span><span class="token punctuation">(</span>num3<span class="token punctuation">)</span>

<span class="token keyword">var</span> largest <span class="token operator">=</span> <span class="token function">max</span><span class="token punctuation">(</span>num1<span class="token punctuation">,</span> num2<span class="token punctuation">,</span> num3<span class="token punctuation">)</span>
<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Largest number is"</span></span><span class="token punctuation">,</span> largest<span class="token punctuation">)</span>
</div>

Output

Enter first number
23
Enter second number
1
Enter third number
10
Largest number is 23

Here in the above code, we takes three integer numbers from the user using the readLine() function that are num1 = 23, num2 = 1 and num3 = 10. Now using the max() function we compare all the three numbers with each other and display the largest number which is 23.

Finding largest number by comparing values

We can also find the largest number among three numbers by comparing all the numbers with each other using > operator.

Algorithm

The algorithm is explained below ?

• Step 1 ? Create a function.

• Step 2 ? Use if-else-if statement and compare the three numbers- n1, n2, and n3 using > operator.

• Step 3 ? Call the function with three arguments

• Step 4 ? Display the output

Example

The following program shows how to find the largest among three numbers by comparing values.

<div class="execute"></div><div class="code-mirror  language-swift" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">import</span> <span class="token class-name">Foundation</span>
<span class="token keyword">import</span> <span class="token class-name">Glibc</span>

<span class="token keyword">func</span> <span class="token function-definition function">maximumValue</span><span class="token punctuation">(</span>n1<span class="token punctuation">:</span> <span class="token class-name">Int</span><span class="token punctuation">,</span> n2<span class="token punctuation">:</span> <span class="token class-name">Int</span><span class="token punctuation">,</span> n3<span class="token punctuation">:</span> <span class="token class-name">Int</span><span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">Int</span><span class="token punctuation">{</span>

   <span class="token comment">// Comparing n1, n2 and n3 with </span>
   <span class="token comment">// each other to find the largest number</span>
   <span class="token keyword">if</span> n1 <span class="token operator">></span> n2<span class="token punctuation">,</span> n1 <span class="token operator">></span> n3<span class="token punctuation">{</span>
      <span class="token keyword">return</span> n1
   <span class="token punctuation">}</span>
   <span class="token keyword">else</span> <span class="token keyword">if</span> n2 <span class="token operator">></span> n3<span class="token punctuation">,</span> n2 <span class="token operator">></span> n1<span class="token punctuation">{</span>
      <span class="token keyword">return</span> n2
   <span class="token punctuation">}</span>
   <span class="token keyword">else</span> <span class="token keyword">if</span> n3 <span class="token operator">></span> n2<span class="token punctuation">,</span> n3 <span class="token operator">></span> n1<span class="token punctuation">{</span>
      <span class="token keyword">return</span> n3
   <span class="token punctuation">}</span>
   <span class="token keyword">else</span> <span class="token keyword">if</span> n1 <span class="token operator">==</span> n2<span class="token punctuation">,</span> n2 <span class="token operator">></span> n3<span class="token punctuation">{</span>
      <span class="token keyword">return</span> n1
   <span class="token punctuation">}</span>
   <span class="token keyword">else</span> <span class="token keyword">if</span> n2 <span class="token operator">==</span> n3<span class="token punctuation">,</span> n3 <span class="token operator">></span> n1<span class="token punctuation">{</span>
      <span class="token keyword">return</span> n2
   <span class="token punctuation">}</span>
   <span class="token keyword">else</span><span class="token punctuation">{</span>
      <span class="token keyword">return</span> n1
   <span class="token punctuation">}</span> 
<span class="token punctuation">}</span>
<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Maximum number is-"</span></span><span class="token punctuation">,</span> <span class="token function">maximumValue</span><span class="token punctuation">(</span>n1<span class="token punctuation">:</span> <span class="token number">2</span><span class="token punctuation">,</span> n2<span class="token punctuation">:</span> <span class="token number">4</span><span class="token punctuation">,</span> n3<span class="token punctuation">:</span> <span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token function">print</span><span class="token punctuation">(</span><span class="token string-literal"><span class="token string">"Maximum number is-"</span></span><span class="token punctuation">,</span> <span class="token function">maximumValue</span><span class="token punctuation">(</span>n1<span class="token punctuation">:</span> <span class="token operator">-</span><span class="token number">19</span><span class="token punctuation">,</span> n2<span class="token punctuation">:</span> <span class="token number">34</span><span class="token punctuation">,</span> n3<span class="token punctuation">:</span> <span class="token number">19</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

Maximum number is- 6
Maximum number is- 34

Here in the above code, we create a function named as maximumValue(), which will return the maximum number among the given three numbers. In this function, we use an if-else-if loop to compare all the numbers with each other with the help of the > operator. Now we call the function two time with different parameter values that is maximumValue(n1: 2, n2: 4, n3: 6) and maximumValue(n1: -19, n2: 34, n3: 19) and display the maximum values that are 6 out of (2, 4, 6) and 34 out of(-19, 34, 19) on the output screen.