# How to convert Decimal to Octal in C++

In this article, we are going to learn how to convert Decimal to Octal in C++. Here we are going to learn about two number systems one is octal and another is Decimal. Octal numbers are based on 8 numbers and are represented in numbers from 0 to 7. Decimal numbers are base 10 numbers and are represented in numbers from 0 to 9.

### C++ Program to convert Decimal to Octal

We will write the below program to convert Decimal to octal with any built-in function.

```#include<iostream>

using namespace std;

int main()
{
long long decimalNum, tmpDecimalNo;
long long octalNum;
int i, rem, place = 1;

octalNum = 0;

cout << "Please enter the decimal number: ";
cin >> decimalNum;

tmpDecimalNo = decimalNum;

while(tmpDecimalNo > 0)
{
rem = tmpDecimalNo % 8;

octalNum = (rem * place) + octalNum;

tmpDecimalNo = tmpDecimalNo/8;

place *= 10;
}

cout << "\nThe Octal equivalent of Decimal number " << decimalNum << " is " << octalNum;

return 0;
}

```

Output

```Please enter the decimal number: 25

The Octal equivalent of Decimal number 25 is 31

```