# 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 = 011100101
Explanation :
Equivalent binary value of 3: 011
Equivalent binary value of 4: 100
Equivalent binary value of 5: 101

Input : Octal = 120
Output : Binary = 001010000
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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 Ocatl 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``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``000``", binary]) ` `        ``elif` `d ``=``=` `1``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``001``", binary]) ` `        ``elif` `d ``=``=` `2``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``010``", binary]) ` `        ``elif` `d ``=``=` `3``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``011``", binary]) ` `        ``elif` `d ``=``=` `4``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``100``", binary]) ` `        ``elif` `d ``=``=` `5``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``101``", binary]) ` `        ``elif` `d ``=``=` `6``: ` `             `  `            ``# concatination of string using join function ` `            ``binary ``=` `"``".join(["``110``",binary]) ` `        ``elif` `d ``=``=` `7``: ` `             `  `            ``# concatination 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 Ocatl to Binary ` `    ``System.Console.WriteLine(``"Equivalent Binary Value = "` `+  ` `                                         ``OctToBin(octnum)); ` `} ` `} ` ` `  `// This code is contributed by mits `

## PHP

 `

Output:

```Equivalent Binary Value = 011100101
```

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