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Program to Convert Octal Number to Binary Number
  • Last Updated : 07 Jan, 2020
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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

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 <iostream>
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<octnum.length()) {
          
        char c=octnum.charAt((int)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.out.println( "\nInvalid Octal Digit "+ octnum.charAt((int)i));
            break;
        }
        i++;
    }
   
    return binary;
}
   
// Driver code
public static void main(String args[])
{
    // Get the Hexadecimal number
    String octnum = "345";
   
    // Convert Ocatl to Binary
    System.out.println( "Equivalent Binary Value = "+ OctToBin(octnum));
   
}
  
}
//contributed by Arnab Kundu

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




<?php
// PHP program to convert
// Octal number to Binary
  
// Function to convert an
// Octal to Binary Number
function OctToBin($octnum)
{
    $i = 0;
  
    $binary = (string)"";
  
    while ($i != strlen($octnum))
    {
        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:
            echo("\nInvalid Octal Digit "
                             $octnum[$i]);
            break;
        }
        $i++;
    }
    return $binary;
  
// Driver code
  
// Get the Hexadecimal number
$octnum = "345";
  
/// Convert Ocatl to Binary
echo("Equivalent Binary Value = "
                OctToBin($octnum));
  
// This code is contributed
// by PrinciRaj1992 
Output:
Equivalent Binary Value = 011100101

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