# C Program to Convert Decimal to Octal using Recursion and Loop1 min read

In this tutorial, we will write a program to convert decimal to octal in C. Before that, you must have knowledge of the following topics in C.

### Octal number

The octal numbers are the numbers with base 8 and use the digits 0 to 7. Example: 8 in decimal is represented as 10 in octal, 25 as 31, and so on.

### Decimal Number

These are the numbers with a base of 10, which ranges from 0 to 9. These numbers are formed with the combination of 0 to 9 digits such as 24, 345, etc.

Example:

`Input: 256Output: 400`

Let us go through a program for the Decimal to Octal Conversion in C.

## 1. Using While loop

Here, we will write a C program to convert decimal number to octal number using while loop. The program simply takes a decimal number as an input from the user and after calculation gives an octal output.

Output:

`Enter a Decimal number: 256Equivalent Octal Value: 400`

## 2. Using Recursion

Here, we will convert a decimal number to octal number using recursion in C. Learn more on Recursion and its use.

Output: After the successful execution of the program, it will produce the same out as the above program.

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