Golang Program To Print Star Pascals Triangle

In this tutorial, we will learn how to print star Pascal?s triangle using Go programming language

Example 1: Golang Code To Print Star Pascal Triangle Using Strconv Package

Syntax

func Itoa(x int) string

Itoa() function takes in an integer parameter and returns the string representation of x when the base is 10

Algorithm

• Step 1 ? Import the package fmt and strconv package.

• Step 2 ? Start function main ().

• Step 3 ? Declare and initialize the variables.

• Step 4 ? Use of for loop with condition and incrementor.

• Step 5 ? Print the result using fmt.Println ().

Example

<div class="execute"></div><div class="code-mirror  language-java" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token comment">// GOLANG PROGRAM TO PRINT STAR PASCALS TRIANGLE</span>
<span class="token keyword">package</span> <span class="token namespace">main</span>

<span class="token comment">// fmt package provides the function to print anything</span>
<span class="token comment">// Package strconv implements conversions to and from</span>
<span class="token comment">// string representations of basic data types</span>
<span class="token keyword">import</span> <span class="token punctuation">(</span>
   <span class="token string">"fmt"</span>
   <span class="token string">"strconv"</span>
<span class="token punctuation">)</span>

<span class="token comment">// start function main ()</span>
func <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

   <span class="token comment">// declare the variables</span>
   <span class="token keyword">var</span> i<span class="token punctuation">,</span> j<span class="token punctuation">,</span> rows<span class="token punctuation">,</span> num <span class="token keyword">int</span>
   
   <span class="token comment">// initialize the rows variable</span>
   rows <span class="token operator">=</span> <span class="token number">7</span>
   
   <span class="token comment">// Scanln() function scans the input, reads and stores</span>
   <span class="token comment">//the successive space-separated values into successive arguments</span>
   <span class="token class-name"><span class="token namespace">fmt<span class="token punctuation">.</span></span>Scanln</span><span class="token punctuation">(</span><span class="token operator">&</span>rows<span class="token punctuation">)</span>
   <span class="token class-name"><span class="token namespace">fmt<span class="token punctuation">.</span></span>Println</span><span class="token punctuation">(</span><span class="token string">"GOLANG PROGRAM TO PRINT STAR PASCALS TRIANGLE"</span><span class="token punctuation">)</span>
   
   <span class="token comment">// Use of For Loop</span>
   <span class="token comment">// This loop starts when i = 0</span>
   <span class="token comment">// executes till i<rows condition is true</span>
   <span class="token comment">// post statement is i++</span>
   <span class="token keyword">for</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> rows<span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
      num <span class="token operator">=</span> <span class="token number">1</span>
      <span class="token class-name"><span class="token namespace">fmt<span class="token punctuation">.</span></span>Printf</span><span class="token punctuation">(</span><span class="token string">"%"</span><span class="token operator">+</span><span class="token class-name"><span class="token namespace">strconv<span class="token punctuation">.</span></span>Itoa</span><span class="token punctuation">(</span><span class="token punctuation">(</span>rows<span class="token operator">-</span>i<span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token operator">+</span><span class="token string">"s"</span><span class="token punctuation">,</span> <span class="token string">""</span><span class="token punctuation">)</span>
      
      <span class="token comment">// run next loop as for (j=0; j<=i; j++)</span>
      <span class="token keyword">for</span> j <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> j <span class="token operator"><=</span> i<span class="token punctuation">;</span> j<span class="token operator">++</span> <span class="token punctuation">{</span>
         <span class="token class-name"><span class="token namespace">fmt<span class="token punctuation">.</span></span>Printf</span><span class="token punctuation">(</span><span class="token string">"%4d"</span><span class="token punctuation">,</span> num<span class="token punctuation">)</span>
         num <span class="token operator">=</span> num <span class="token operator">*</span> <span class="token punctuation">(</span>i <span class="token operator">-</span> j<span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token punctuation">(</span>j <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span>
      <span class="token punctuation">}</span>
      
      <span class="token class-name"><span class="token namespace">fmt<span class="token punctuation">.</span></span>Println</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
      <span class="token comment">// print the result</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

GOLANG PROGRAM TO PRINT STAR PASCALS TRIANGLE
                 1
               1   1
             1   2   1
           1   3   3   1
         1   4   6   4   1
       1   5  10  10   5   1
     1   6  15  20  15   6   1

Description Of The Code

• In the above program, we first declare the package main.

• We imported the fmt package that includes the files of package fmt. We also imported Package strconv implements conversions to and from string representations of basic data types.

• Now start the function main().

• Declare the four integer variables i, j, num and rows. Initialize the rows variable to an integer value you want for Pascal?s triangle pattern. Use fmt.Scanln() to read and store the rows value.

• Using for loop: The condition is given inside an if statement and stop execution is mentioned once the condition is right.

• In the line 28 of the code: The loop starts when i = 0 and executes till i<rows condition is true and the post statement is i++.

• In the line 32 of the code: it runs the next loop as for (j=0; j<=i; j++).

• In this loop the function strconv.Itoa() is called for the calculation of pascal?s triangle.

• And last printing the result in the form of a triangle on the screen using fmt.Println.

Conclusion

We have successfully compiled and executed the Golang program code to print star Pascal?s triangle in the above example.