# Kotlin Program to Convert Octal Number to Binary

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Given an octal number as input. Now, write a Kotlin program to convert Octal number to Binary.

```Input:
7

Output:
111
```
```Input:
120

Output:
001010000
```
```Input:
121

Output:
001010001
```

## 1. Program to Convert Octal to Binary

###### Pseudo Algorithm
• Initialize a variable binaryNum with empty string.
• Now, convert each digit of octal number into binary and append it to binaryNum.
• Repeat till last digit of the octal number.
• Finally, binaryNum will contain binary representation of octal number.

Sourcecode –

```fun main() {

println("Enter n:")

if(checkOctalNumber(octalN!!)) {
val octalNumString: String = octalN

var i = 0
var binaryNum = ""
while(i < octalNumString.length) {
when(octalNumString[i]) {
'0'  -> binaryNum += "000"
'1'  -> binaryNum += "001"
'2'  -> binaryNum += "010"
'3'  -> binaryNum += "011"
'4'  -> binaryNum += "100"
'5'  -> binaryNum += "101"
'6'  -> binaryNum += "110"
'7'  -> binaryNum += "111"
}
i++
}
println("Equivalent Binary : \$binaryNum")
} else {
println("\$octalN is not an octal number")
}
}

private fun checkOctalNumber(octalNum: String): Boolean {
var isOctal = true

for(charAtPos in octalNum) {
if(!((charAtPos >= '0') && (charAtPos <= '7'))) {
isOctal = false
break
}
}
return isOctal
}
```

When you run the program, output will be –

```Enter n:
7657576576575
Equivalent Binary : 111110101111101111110101111110101111101
```
###### Explanation:

We just extract each digit from the original octal number. Then, we converted that digit into binary and appended it with binaryNum
variable. Finally, binaryNum contains binary representation of the octal number.

Thus, we went through Kotlin Program to Convert Octal number to Binary number.