# Kotlin program to convert octal number to binary number

Kotlin | Octal to Binary Conversion: Here, we are going to learn how to convert a given octal number to its equivalent binary number in Kotlin programming language?
Submitted by IncludeHelp, on April 25, 2020

Given a number in octal number system format, we have to convert it into binary number system format.

Example:

```    Input:
num = 123

Output:
1010011
```

### Program to convert octal number to binary number in Kotlin

```package com.includehelp.basic

import java.util.*

//Function to Convert Octal to Decimal
fun convertOctalToDecimal(_octalNumber:Long):Long{
var octalNumber = _octalNumber
var decimalNumber: Long=0
var i = 0

//Convert Octal to Decimal
while (octalNumber > 0) {
val r= octalNumber % 10
decimalNumber += (r * Math.pow(8.0,i.toDouble())).toLong()
octalNumber /= 10
i ++
}

return decimalNumber;
}

/* function to convert given decimal into Binary */
fun convertDecimalToBinary(_decimalNumber: Long): Long {
var decimalNum = _decimalNumber
var binaryNum: Long = 0
var i=1
while (decimalNum > 0) {
binaryNum += (decimalNum % 2 * i)
decimalNum /= 2
i *= 10
}

return binaryNum
}

//Function for Octal to Binary Number
fun octalToBinaryConversion(_octalNumber: Long): Long{
//Call method to convert binary to decimal
val decimal : Long = convertOctalToDecimal(_octalNumber)
println("Decimal : \$decimal")

//Call method to convert decimal to binary
val binary = convertDecimalToBinary(decimal);

return binary
}

//Main function Entry Point of Program
fun main(arg: Array<String>) {
var isCorrectOctal=true;

//Input Stream
val sc = Scanner(System.`in`)

//Input Octal Number
println("Enter Octal Number  : ")
var octalNumber: Long = sc.nextLong()

val octalStr = octalNumber.toString();
//Check Given no is valid Octal Number or not
for(i in octalStr.indices){
if (octalStr[i] !in '0'..'7' ){
isCorrectOctal=false
}
}

if(isCorrectOctal){

val binary = octalToBinaryConversion(octalNumber);

//Print Binary
println("Binary of Octal \$octalNumber is : \$binary")

}else{
System.err.println("Invalid Octal Number !!")
}
}
```

Output

```Run 1:
Enter Octal Number  :
23356549
Invalid Octal Number !!
-------
Run 2:
Enter Octal Number  :
123
Decimal : 83
Binary of Octal 123 is : 1010011
-------
Run 3:
Enter Octal Number  :
234
Decimal : 156
Binary of Octal 234 is : 10011100
```