### C program to find the number of digits in a number :

In this tutorial, we will learn how to find the total number of digits in an integer. For example, the number *123* contains *3* digits. We will learn two different ways to solve this problem. First one is by using a *while loop* and then secondly, by using a *recursive method*.

### Algorithm :

The main algorithm or process we are going to use is as below :

– For example, we are finding the number of digits in *234*.

– Suppose, *count* holds the total number of digits. In the beginning, *count = 0*.

– Divide 234 by 10 . *234/10 = 23*. Increment count -> *count = 1*

– Divide 23 by 10 . *23/10 = 2*. Increment count -> *count = 2*

– Divide 2 by 10 . *2/10 = 0*. Increment count -> *count = 3*

– Since last result was *0*, final result is *3* .

### Find the number of digits using a while loop :

Following C program will find the total number of digits using one *while loop* :

#include<stdio.h> int main(){ //1 int no; int totalDigits = 0; //2 printf("Enter a number : "); scanf("%d",&no); //3 while(no!=0){ //4 no = no/10; totalDigits ++; } //5 printf("Total digits in the number is %d\n",totalDigits); }

### Explanation :

*The commented numbers in the above program denote the step number below :*

1. Create one variable *no* to store the number and one variable *totalDigits* to store the count of digits in the number.

2. Ask the user to enter a number. Read and save it in variable *no*.

3. Run one *while loop*. This loop will run continuously till the number becomes *0*.

4. Inside the loop, divide the *no* by *10* and set this value to *no* itself. Increment the *totalDigits* by one.

5. After the loop is completed, *totalDigits* should hold the total count of digits. Print it out.

### Using recursive method :

In this program, we will use the same approach as above. Only difference is that instead of a while loop, one method will call itself again and again.

#include<stdio.h> //2 int findTotalDigits(int no){ //3 if(no == 0){ return 0; } //4 return 1 + findTotalDigits(no/10); } int main(){ int no; int totalDigits = 0; printf("Enter a number : "); scanf("%d",&no); //1 totalDigits = findTotalDigits(no); printf("Total digits in the number is %d\n",totalDigits); }

### Explanation :

1. In this program, *findTotalDigits()* function is used to fing the total count. It returns the total count and we are storing it in *totalDigits* variable.

2. *findTotalDigits()* takes one integer as input and return one integer (total count).

3. If the provided number is *0*, return *1*.

4. Else return *1 + findTotalDigits(no/10)* , i.e. call the same method again.

– For number *123* , it will return *1 + findTotalDigits(12)* .

– *findTotalDigits(12)* will return *1 + findTotalDigits(1)*.

– *findTotalDigits(1)* will return *1 + findTotalDigits(0)*.

– *findTotalDigits(0)* will return *0* ( as mentioned on step 3).

So, finally it will rreturn *1 + 1 + 1 = 3* for *123*.

### Sample Outputs :

Enter a number : 123 Total digits in the number is 3 Enter a number : 1234567 Total digits in the number is 7 Enter a number : 889383 Total digits in the number is 6

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