C++ Program for Binary to Octal conversion

November 24, 2022

Binary to Octal conversion in C++

Here, we will discuss binary to octal conversion in C++.There are two approaches of converting an octal number into a binary number like

  • grouping the binary number into pairs of three and converting into octal.
  • By converting the binary number into a decimal number first and then convert that decimal number into an octal number.

We are using second approach, this approach is long but it is very easy to implement and also the chances of error are also very minimum.

Binary to octal

Method 1:-

We will first convert the Binary number into Decimal and then convert the Decimal number into Octal

Make sure that you have gone through these approaches below –

  1. Binary to Decimal Conversion
  2. Decimal to Octal Conversion

Method 1 Code

Run 
#include<iostream>
#include<math.h>
using namespace std;

// function to convert binary to octal
void convert(long long num)
{
    int octalDigit = 0, count = 1, i = 0, pos = 0;
    int octalArray[32] = {0};

    while(num != 0)
    {
        int digit = num % 10;
        
        octalDigit += digit * pow(2, i);
        i++;
        num /= 10;
        
        // placing current octalsum for 3 pair in array index position
        octalArray[pos] = octalDigit;
        
        // whenever we have read next 3 digits
        // setting values to default
        // increasing pos so next values can be placed at next array index
        if(count % 3 == 0)
        {
            octalDigit = 0;
            i = 0;
            pos++;
        }
        count++;
    }
        
    // printing octal array in reverse order
    for (int j = pos; j >= 0; j--)
        cout<<octalArray[j];

}

//main program
int main()
{
    // long used rather than int to store large values
    long long binary;
    
    printf("Enter binary number: ");
    scanf("%lld", &binary);
    
    convert(binary);
    
    return 0;
}

Output :

Enter binary number: 1010
Decimal : 10
Octal : 12
Binary to octal conversion in C++

Method 2 Code

Run 
#include<iostream>
#include<math.h>
using namespace std;

// function to convert binary to octal
void convert(long long num)
{
    int octalDigit = 0, count = 1, i = 0, pos = 0;
    int octalArray[32] = {0};

    while(num != 0)
    {
        int digit = num % 10;
        
        octalDigit += digit * pow(2, i);
        i++;
        num /= 10;
        
        // placing current octalsum for 3 pair in array index position
        octalArray[pos] = octalDigit;
        
        // whenever we have read next 3 digits
        // setting values to default
        // increasing pos so next values can be placed at next array index
        if(count % 3 == 0)
        {
            octalDigit = 0;
            i = 0;
            pos++;
        }
        count++;
    }
        
    // printing octal array in reverse order
    for (int j = pos; j >= 0; j--)
        cout<<octalArray[j];

}

//main program
int main()
{
    // long used rather than int to store large values
    long long binary;
    
    printf("Enter binary number: ");
    scanf("%lld", &binary);
    
    convert(binary);
    
    return 0;
}

Output :

Enter binary number: 010101
25
While loop in C

Method 2:-

Method 2 uses the concept of grouping 3 successive digits/bits of the binary number and calculating octal digits against each grouping

We use an additional array to store the octal digits at each index.

We will need to print the array in reverse to get actual octal equivalent.

Decimal to Binary conversion

Decimal to Octal Conversion

Decimal to Hexadecimal Conversion

Permutations in which n people can occupy r seats in a classroom 

Octal to Binary conversion

Quadrants in which a given coordinate lies

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While loop in C
While loop in C

2 comments on “C++ Program for Binary to Octal conversion”


  • Y.PRAVEEN

    //using if else updated one
    #include
    using namespace std;

    int main() {
    int num;
    cout << "Enter a binery number" <> num;

    if (num == 000) {
    cout << "0";
    }
    else if (num == 001) {
    cout << "1";
    }
    else if (num == 010 || num == 10) {
    cout << "2";
    }
    else if (num == 011 || num == 11) {
    cout << "3";
    }
    else if (num == 100) {
    cout << "4";
    }
    else if (num == 101) {
    cout << "5";
    }
    else if (num == 110) {
    cout << "6";
    }
    else if (num == 111) {
    cout << "7";
    }
    else {
    cout << "Not an octal number" << endl;
    cout << "Please enter binery number between 000 to 111" <0″);
    return 0;
    }

    0

  • Y.PRAVEEN

    //using if else
    #include
    using namespace std;

    int main() {
    int num;
    cout << "enter a binery number"<> num;

    if ( num == 0) {
    cout << "0";
    }
    else if ( num == 001 ) {
    cout << "1";
    }
    else if (num == 010 || num == 10) {
    cout << "2";
    }
    else if (num == 011 || num == 11) {
    cout << "3";
    }
    else if (num == 100) {
    cout << "4";
    }
    else if (num == 101) {
    cout << "5";
    }
    else if (num == 110) {
    cout << "6";
    }
    else {
    cout <0″);
    return 0;
    }

    1