Binary to Octal Conversion

“Binary to Octal Conversion” is one of the classic programming exercise problem for beginners. Here, we are given a Binary Number, entered by user and our task is to write a program to convert the binary number to its equivalent octal number.

Example:

Binary = 100011011
Octal = 433

The steps required to convert the Binary Number to Octal Number are as follows:

1. Make sure the number of digits in binary number is divisible by 3. If not, add extra 0s in front.
2. Divide the binary number into pairs of 3-digit binary number.
3. Convert each 3-digit binary number pair to its decimal form.
4. Combine all the decimal numbers and store into ‘Octal’.
5. Print the result.

C++ Program to Convert Binary to Octal is as follows:

/* C++ Program to Convert Binary Number to Octal Number*/  
#include<bits/stdc++.h>  
using namespace std;  
int main()  
{  
    /* Scan the Binary Number */  
    string Binary;  
    cout<<"Enter the Binary Number: ";  
    cin>>Binary;  
      
    /* Converting Binary to Octal*/  
      
    /* Make sure the number of digits in 'Binary'  
       Number is divisible by 3. If not, add  
       required 0s in front*/  
    while(Binary.length() % 3 != 0)  
    {  
        Binary.insert(0,"0");  
    }  
      
    /* Converting each digit of Binary number 
       into 3-digit binary number pair and convert 
       each pair to its corresponding decimal 
    */  
    string Octal = "";  
    for(int i = 0; i < Binary.length(); i=i+3)  
    {  
        string temp;  
        temp = temp + Binary[i];  
        temp = temp + Binary[i+1];  
        temp = temp + Binary[i+2];  
        if(temp == "000")  
            Octal += '0';  
        else if(temp == "001")  
            Octal += '1';  
        else if(temp == "010")   
            Octal += '2';  
        else if(temp == "011")  
            Octal += '3';  
        else if(temp == "100")  
            Octal += '4';  
        else if(temp == "101")  
            Octal += '5';  
        else if(temp == "110")  
            Octal += '6';  
        else if(temp == "111")  
            Octal += '7';  
    }  
      
    /*Printing the result */  
    cout<<"The Octal of "<<Binary<<" is "<<Octal;  
}  

OUTPUT:
Enter the Binary Number: 100011011
 The Octal of 100011011 is 433