# C Program to Convert Octal to Decimal1 min read

In this tutorial, we will write a program to convert octal to decimal in C using whille loop. 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: 400Output: 256`

Let us go through a program for the Octal to Decimal Conversion in C. we will perform two different C programs.

1. Basic program
2. Using user-defined function

## C Program to Convert Octal to Decimal

Source code:

Output:

`Enter an octal number: 400Equivalent Decimal Value: 256`

## Using Function

Source code: convert octal to decimal using function in C.

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

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