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# Program to Convert Octal Number to Binary Number

Given an Octal number as input, the task is to convert that number to Binary number.

Examples:

Input : Octal = 345
Output : Binary = 11100101
Explanation
Equivalent binary value of 3: 011
Equivalent binary value of 4: 100
Equivalent binary value of 5: 101

Input : Octal = 120
Output : Binary = 1010000

Octal Number: An Octal number is a positional numeral system with a radix, or base, of 8 and uses eight distinct symbols.
Binary Number: A Binary number is a number expressed in the base-2 binary numeral system, which uses only two symbols: which are 0 (zero) and 1 (one).

To convert an Octal number to Binary, the binary equivalent of each digit of the octal number is evaluated and combined at the end to get the equivalent binary number.

Below is the implementation of the above approach:

## C++

 `// C++ program to convert``// Octal number to Binary` `#include ``using` `namespace` `std;` `// Function to convert an``// Octal to Binary Number``string OctToBin(string octnum)``{``    ``long` `int` `i = 0;` `    ``string binary = ``""``;` `    ``while` `(octnum[i]) {``        ``switch` `(octnum[i]) {``        ``case` `'0'``:``            ``binary += ``"000"``;``            ``break``;``        ``case` `'1'``:``            ``binary += ``"001"``;``            ``break``;``        ``case` `'2'``:``            ``binary += ``"010"``;``            ``break``;``        ``case` `'3'``:``            ``binary += ``"011"``;``            ``break``;``        ``case` `'4'``:``            ``binary += ``"100"``;``            ``break``;``        ``case` `'5'``:``            ``binary += ``"101"``;``            ``break``;``        ``case` `'6'``:``            ``binary += ``"110"``;``            ``break``;``        ``case` `'7'``:``            ``binary += ``"111"``;``            ``break``;``        ``default``:``            ``cout << ``"\nInvalid Octal Digit "``                 ``<< octnum[i];``            ``break``;``        ``}``        ``i++;``    ``}` `    ``return` `binary;``}` `// Driver code``int` `main()``{``    ``// Get the Hexadecimal number``    ``string octnum = ``"345"``;` `    ``// Convert Octal to Binary``    ``cout << ``"Equivalent Binary Value = "``         ``<< OctToBin(octnum);` `    ``return` `0;``}`

## Java

 `// Java program to convert``// Octal number to Binary``import` `java.util.*;``class` `Solution``{`` ` `// Function to convert an``// Octal to Binary Number``static` `String OctToBin(String octnum)``{``    ``long` `i = ``0``;`` ` `    ``String binary = ``""``;``    ` `    ``while` `(i

## Python3

 `# Python3 program to convert``# Octal number to Binary` `# defining a function that returns``# binary equivalent of the number``def` `OctToBin(octnum):``    ` `    ``binary ``=` `"" ``# initialising bin as String``    ` `    ``# While loop to extract each digit``    ``while` `octnum !``=` `0``:``        ` `        ``# extracting each digit``        ``d ``=` `int``(octnum ``%` `10``)``        ``if` `d ``=``=` `0``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``000``", binary])``        ``elif` `d ``=``=` `1``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``001``", binary])``        ``elif` `d ``=``=` `2``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``010``", binary])``        ``elif` `d ``=``=` `3``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``011``", binary])``        ``elif` `d ``=``=` `4``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``100``", binary])``        ``elif` `d ``=``=` `5``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``101``", binary])``        ``elif` `d ``=``=` `6``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``110``",binary])``        ``elif` `d ``=``=` `7``:``            ` `            ``# concatenation of string using join function``            ``binary ``=` `"``".join(["``111``", binary])``        ``else``:``            ` `            ``# an option for invalid input``            ``binary ``=` `"Invalid Octal Digit"``            ``break` `        ``# updating the oct for while loop``        ``octnum ``=` `int``(octnum ``/` `10``)``        ` `    ``# returning the string binary that stores``    ``# binary equivalent of the number``    ``return` `binary` `# Driver Code``octnum ``=` `345` `# value of function stored final_bin``final_bin ``=` `"" ``+` `OctToBin(octnum)` `# result is printed``print``(``"Equivalent Binary Value ="``, final_bin)` `# This code is contributed by Animesh_Gupta`

## C#

 `// C# program to convert Octal number to Binary` `class` `GFG``{` `// Function to convert an``// Octal to Binary Number``static` `string` `OctToBin(``string` `octnum)``{``    ``int` `i = 0;` `    ``string` `binary = ``""``;``    ` `    ``while` `(i < octnum.Length)``    ``{``        ` `        ``char` `c = octnum[i];``        ``switch` `(c)``        ``{``        ``case` `'0'``:``            ``binary += ``"000"``;``            ``break``;``        ``case` `'1'``:``            ``binary += ``"001"``;``            ``break``;``        ``case` `'2'``:``            ``binary += ``"010"``;``            ``break``;``        ``case` `'3'``:``            ``binary += ``"011"``;``            ``break``;``        ``case` `'4'``:``            ``binary += ``"100"``;``            ``break``;``        ``case` `'5'``:``            ``binary += ``"101"``;``            ``break``;``        ``case` `'6'``:``            ``binary += ``"110"``;``            ``break``;``        ``case` `'7'``:``            ``binary += ``"111"``;``            ``break``;``        ``default``:``            ``System.Console.WriteLine( ``"\nInvalid Octal Digit "``+``                                                    ``octnum[i]);``            ``break``;``        ``}``        ``i++;``    ``}` `    ``return` `binary;``}` `// Driver code``static` `void` `Main()``{``    ``// Get the Hexadecimal number``    ``string` `octnum = ``"345"``;` `    ``// Convert Octal to Binary``    ``System.Console.WriteLine(``"Equivalent Binary Value = "` `+``                                         ``OctToBin(octnum));``}``}` `// This code is contributed by mits`

## PHP

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## Javascript

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Output:

`Equivalent Binary Value = 011100101`

Time complexity: O(n) where n is no of digits in a given number.
Auxiliary space: O(n) it is using extra space for binary string.

#### define function to convert octal to binary in python:

Approach:

n this program, we define a function called octal_to_binary that takes an octal number as input and returns its binary equivalent.

The function works by first converting the octal number to decimal using the repeated division by 8 technique. Once we have the decimal equivalent, we can convert it to binary using the repeated division by 2 technique.

Finally, we call the octal_to_binary function with a sample octal number of 777, and then print the binary equivalent using an f-string.

## C++

 `#include ``#include ``using` `namespace` `std;` `int` `octal_to_binary(``int` `octal) {``    ``// Converting Octal to Decimal``    ``int` `decimal = 0;``    ``int` `power = 0;``    ``while` `(octal != 0) {``        ``decimal += (octal % 10) * ``pow``(8, power);``        ``octal /= 10;``        ``power++;``    ``}` `    ``// Converting Decimal to Binary``    ``int` `binary = 0;``    ``int` `digit_place = 1;``    ``while` `(decimal != 0) {``        ``binary += (decimal % 2) * digit_place;``        ``decimal /= 2;``        ``digit_place *= 10;``    ``}` `    ``return` `binary;``}` `int` `main() {``    ``// Sample Input``    ``int` `octal_number = 777;` `    ``// Octal to Binary Conversion``    ``int` `binary_number = octal_to_binary(octal_number);` `    ``// Output``    ``cout << binary_number << endl;` `    ``return` `0;``}`

## Java

 `import` `java.util.Scanner;` `public` `class` `Main {``    ``public` `static` `int` `octal_to_binary(``int` `octal)``    ``{``        ``// Converting Octal to Decimal``        ``int` `decimal = ``0``;``        ``int` `power = ``0``;``        ``while` `(octal != ``0``) {``            ``decimal += (octal % ``10``) * Math.pow(``8``, power);``            ``octal /= ``10``;``            ``power++;``        ``}` `        ``// Converting Decimal to Binary``        ``int` `binary = ``0``;``        ``int` `digit_place = ``1``;``        ``while` `(decimal != ``0``) {``            ``binary += (decimal % ``2``) * digit_place;``            ``decimal /= ``2``;``            ``digit_place *= ``10``;``        ``}` `        ``return` `binary;``    ``}` `    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Sample Input``        ``int` `octal_number = ``777``;` `        ``// Octal to Binary Conversion``        ``int` `binary_number = octal_to_binary(octal_number);` `        ``// Output``        ``System.out.println(binary_number);``    ``}``}`

## Python3

 `# Octal to Binary Conversion Function``def` `octal_to_binary(octal):``    ``# Converting Octal to Decimal``    ``decimal ``=` `0``    ``power ``=` `0``    ``while` `octal !``=` `0``:``        ``decimal ``+``=` `(octal ``%` `10``) ``*` `pow``(``8``, power)``        ``octal ``/``/``=` `10``        ``power ``+``=` `1` `    ``# Converting Decimal to Binary``    ``binary ``=` `0``    ``digit_place ``=` `1``    ``while` `decimal !``=` `0``:``        ``binary ``+``=` `(decimal ``%` `2``) ``*` `digit_place``        ``decimal ``/``/``=` `2``        ``digit_place ``*``=` `10` `    ``return` `binary` `# Sample Input``octal_number ``=` `777` `# Octal to Binary Conversion``binary_number ``=` `octal_to_binary(octal_number)` `# Output``print``(f``"The binary equivalent of {octal_number} is {binary_number}"``)`

## C#

 `using` `System;` `class` `Program {``    ``static` `int` `octal_to_binary(``int` `octal) {``        ``// Converting Octal to Decimal``        ``int` `decimalNumber = 0;``        ``int` `power = 0;``        ``while` `(octal != 0) {``            ``decimalNumber += (octal % 10) * (``int``)Math.Pow(8, power);``            ``octal /= 10;``            ``power++;``        ``}` `        ``// Converting Decimal to Binary``        ``int` `binaryNumber = 0;``        ``int` `digit_place = 1;``        ``while` `(decimalNumber != 0) {``            ``binaryNumber += (decimalNumber % 2) * digit_place;``            ``decimalNumber /= 2;``            ``digit_place *= 10;``        ``}` `        ``return` `binaryNumber;``    ``}` `    ``static` `void` `Main() {``        ``// Sample Input``        ``int` `octalNumber = 777;` `        ``// Octal to Binary Conversion``        ``int` `binaryNumber = octal_to_binary(octalNumber);` `        ``// Output``        ``Console.WriteLine(binaryNumber);``    ``}``}`

## Javascript

 `function` `octal_to_binary(octal)``{` `    ``// Converting Octal to Decimal``    ``let decimal = 0;``    ``let power = 0;``    ``while` `(octal != 0) {``        ``decimal += (octal % 10) * Math.pow(8, power);``        ``octal = Math.floor(octal / 10);``        ``power++;``    ``}` `    ``// Converting Decimal to Binary``    ``let binary = 0;``    ``let digit_place = 1;``    ``while` `(decimal != 0) {``        ``binary += (decimal % 2) * digit_place;``        ``decimal = Math.floor(decimal / 2);``        ``digit_place *= 10;``    ``}` `    ``return` `binary;``}` `// Sample Input``const octal_number = 777;` `// Octal to Binary Conversion``const binary_number = octal_to_binary(octal_number);` `// Output``console.log(`The binary equivalent of \${octal_number} is \${binary_number}`);`

Output

`The binary equivalent of 777 is 111111111`

The time complexity: O(log n). Where n is the input octal number

The auxiliary space : O(1) .

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