# C++ Program to find number of digits in an integer

## Finding number of digits in an integer in C++

Here we will discuss how to find the number of digits in an integer in c++ programming language.

An integer is made up a number of digits i.e. a number is a combination of 0-9. Example 9825 is any integer which has 4 digits. ## Method Discussed :

• Method 1 : Using loop
• Method 2 : Using formulae.

Let’s discuss above two methods in brief,

## Method 1:

Let’s see how the code works:

• The user will give an input.
• The input will be stored in an int type variable say num.
• do while loop is started
• Divide num by 10 and store result in num itself

num=num/10;

• Every time num is divided by 10 increment digit by 1

digit++;.

• Do this until num is not equal to 0

while(num!=0);

• digit is printed which is the number of digits in num.

### Method 1 : Code in C++

Run
```#include<bits/stdc++.h>
using namespace std;

int main(){
int num = 20901;
int digit = 0;

while(num>0){
digit++;
num = num/10;
}
cout<<"No. of digits = "<< digit;

}
```

### Output

```No. of digits = 5
```

## Method 2 :

In this method we will simple use the mathematical formulae,

• No. of digits : floor(log10(n))+1

### Method 2 : Code in C++

Run
```#include<bits/stdc++.h>
#include<iostream>

using namespace std;

int
main ()
{

int num = 20901;

int digit = floor (log10 (num)) + 1;

cout << "No. of digits = " << digit;

}

```

### Output

```No. of digits = 5
```