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C Program to Count Number of Digits in an Integer

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In this tutorial, we will write a program to count the number of digits in an integer in C language. For example, if we have to count how many digits are there is an integer number &ldquo;36810&rdquo;. To find out the number of digits we will keep dividing the given number by &ldquo;10&rdquo; until the number becomes zero as shown in figure 1:
Note: We have to count how many times the number is divided by &ldquo;10&rdquo; before its value become &ldquo;0&rdquo; 
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/c-practice-programs-in-hindi-16/base64.webp" />
Figure 1: Method to count digits in a number
As shown in figure 1, the given number is &ldquo;36801&rdquo; and we have to count its digit. We will divide the number by &ldquo;10&rdquo;,
<ol>
<li>When we divided the number &ldquo;36810&rdquo; with &ldquo;10&rdquo;; the remaining value is &ldquo;3681&rdquo; and the value of count is now &ldquo;1&rdquo;</li>
<li>When we divided the number &ldquo;3681&rdquo; with &ldquo;10&rdquo;; the remaining value is &ldquo;368&rdquo; and the value of count is now &ldquo;2&rdquo;</li>
<li>When we divided the number &ldquo;368&rdquo; with &ldquo;10&rdquo;; the remaining value is &ldquo;36&rdquo; and the value of count is now &ldquo;3&rdquo;</li>
<li>When we divided the number &ldquo;36&rdquo; with &ldquo;10&rdquo;; the remaining value is &ldquo;3&rdquo; and the value of count is now &ldquo;4&rdquo;</li>
<li>When we divided the number &ldquo;3&rdquo; with &ldquo;10&rdquo;; the remaining value is &ldquo;0&rdquo; and the value of count is now &ldquo;5&rdquo;</li>
</ol>
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By using this technique we have figured it out that there are &ldquo;5&rdquo; digits in the number &ldquo;36810&rdquo;. The C program of this example is shown below:
C program to count number if digits is an integer
<pre class="language-cpp"><code>int main(){

 int n, counter = 0;

 printf(&ldquo;Enter the number\n&rdquo;);

 scanf(&ldquo;%d&rdquo;, &amp;n)</code></pre>
Code Snippet 1: Main Program 1
As shown in the code snippet 1,
<ol>
<li>We have declared an integer variable &ldquo;n&rdquo; which will be used to store the number which user will input.</li>
<li>We have initialized an integer variable &ldquo;Counter&rdquo; and assigned a value &ldquo;0&rdquo; to it; the counter will be used to count how many times number is divided</li>
<li>The function &ldquo;printf&rdquo; is used to print &ldquo;Enter the number&rdquo;</li>
<li>And the function &ldquo;scanf&rdquo; is used to take input from the user at run time</li>
</ol>
<pre class="language-cpp"><code>if(n==0)
printf(&ldquo;There is only 1 digit in your number&rdquo;);

else
{
while (n !=0 )

{

n = n/10;

counter++:

}

printf(&ldquo;There are %d digits in your number &rdquo;, counter);

return 0;
}</code></pre>
Code Snippet 2: Main program 2
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As shown in the code snippet 2,
<ol>
<li>We have used an &ldquo;if&rdquo; condition to check that if the number entered by the user is &ldquo;0&rdquo;. It will simply print that &ldquo;There is only 1 digit in your number&rdquo;</li>
<li>In the &ldquo;else&rdquo; we have used a &ldquo;while&rdquo; loop which will run till the value of &ldquo;n&rdquo; is not equal to &ldquo;0&rdquo;; in the body of while loop the value of &ldquo;n&rdquo; will be divide by &ldquo;10&rdquo; at each iteration; and the value of the counter will be incremented by &ldquo;1&rdquo;</li>
<li>When the loops end the value of the &ldquo;counter&rdquo; will be printed this will tell us how many numbers are there in the given digit.</li>
</ol>
The output of the following program is shown in figure 2
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/c-practice-programs-in-hindi-16/base64_M8tv3ZL.webp" />
Figure 2: Program Output 1
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/c-practice-programs-in-hindi-16/base64_aefkQWJ.webp" />
Figure 3: Program Output 2