Write a C program to count frequency of digits in a given number. How to find frequency of digits in a given number using loop in C programming. Logic to find total occurrences of each digits in a given number in C program.

**Example**

**Input**

Input any number: 116540

**Output**

Frequency of 0 = 1 Frequency of 1 = 2 Frequency of 2 = 0 Frequency of 3 = 0 Frequency of 4 = 1 Frequency of 5 = 1 Frequency of 6 = 1 Frequency of 7 = 0 Frequency of 8 = 0 Frequency of 9 = 0

## Required knowledge

Basic C programming, Loop, Array

Must know -

## Logic to find frequency of digits in any number

Below is the step by step description to count frequency of digits in an integer.

- Input a number from user. Store it in some variable say num.
- Declare an array to hold frequency of size 10 i.e. freq[10]. Now why size 10? Because total number of digits is
`10 0, 1, 2, ... , 8, 9`

. - Initialize all elements of frequency array with
`0`

i.e. freq[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}. Assuming that the 0th index will hold the frequency of 0. 1st index will hold frequency of 1. So on 9th index of freq will store the frequency of 9. - Extract the last digit of number by performing modulo division by 10. Store the last digit in some variable say lastDigit = num % 10. The value in lastDigit is always between
`0-9`

inclusive. This last digit can be used as an index to freq array. - Increment the frequency value of lastDigit found above. Using freq[lastDigit]++.
- Remove last digit of the number. As it is processed and not required further. Divide the number by 10 to remove last digit i.e. num = num / 10.
- Repeat step 4-6 till number is greater than 0.

## Program to count frequency of digits in a number

```
/**
* C program to count frequency of digits in a given number
*/
#include <stdio.h>
#define BASE 10
int main()
{
long long num, n;
int i, lastDigit;
int freq[BASE];
printf("Enter any number: ");
scanf("%lld", &num);
// Initialize frequency array with 0
for(i=0; i<BASE; i++)
{
freq[i] = 0;
}
n = num; // Copy the value of num to n
while(n != 0)
{
// Get last digit
lastDigit = n % 10;
// Remove the last digit
n /= 10;
// Increment the frequency array
freq[lastDigit]++;
}
// Print frequency of each digit
printf("Frequency of each digit in %lld is: \n", num);
for(i=0; i<BASE; i++)
{
printf("Frequency of %d = %d\n", i, freq[i]);
}
return 0;
}
```

**Note:** Do not confuse with the statement n /= 10. It is same as n = n / 10. You can use any of them according to your comfort.

Output

Enter any number: 11203458760011 Frequency of each digit in 11203458760011 is: Frequency of 0 = 3 Frequency of 1 = 4 Frequency of 2 = 1 Frequency of 3 = 1 Frequency of 4 = 1 Frequency of 5 = 1 Frequency of 6 = 1 Frequency of 7 = 1 Frequency of 8 = 1 Frequency of 9 = 0

Happy coding 😉

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