C++ Exercises: Convert a binary number to octal number

Last update on April 07 2025 13:00:58 (UTC/GMT +8 hours)

75. Binary to Octal Conversion

Write a C++ program to convert a binary number to an octal number.

Visual Presentation:

C++ Exercises: Convert a binary number to octal number

Sample Solution:-

C++ Code :

#include <iostream> // Include input/output stream library
#include <math.h>   // Include math library for mathematical functions
using namespace std; // Use the standard namespace

int main() // Main function where the execution of the program starts
{
    int binnum1, binaryNumber, rem, decnum = 0, quot, i = 1, j; // Declare variables for binary, decimal, quotient, and iteration
    int octnum[100]; // Declare an array to store octal digits

    cout << "\n\n Convert a binary number to octal number:\n"; // Display message prompting for binary to octal conversion
    cout << "---------------------------------------------\n"; // Display separator line
    cout << " Input a binary number: "; // Prompt user to input a binary number
    cin >> binaryNumber; // Read the binary number input by the user

    binnum1 = binaryNumber; // Store the input binary number for display later

    while (binaryNumber > 0) // Loop to convert binary to decimal
    {
        rem = binaryNumber % 10; // Calculate the remainder by performing modulo 10 operation
        decnum = decnum + rem * i; // Calculate the decimal number by adding the remainder multiplied by a factor 'i'
        i = i * 2; // Multiply the factor 'i' by 2 for the next iteration
        binaryNumber = binaryNumber / 10; // Update the binary number by removing its last digit (rightmost digit)
    }

    i = 1; // Reset the iteration variable to 1
    quot = decnum; // Store the decimal number in 'quot'

    while (quot > 0) // Loop to convert decimal to octal
    {
        octnum[i++] = quot % 8; // Calculate the remainder after dividing by 8 and store it in the octal array
        quot = quot / 8; // Update the quotient by dividing by 8
    }

    cout << " The equivalent octal value of " << binnum1 << " is : "; // Display the equivalent octal value
    for (j = i - 1; j > 0; j--) // Loop to display the octal digits
    {
        cout << octnum[j]; // Display octal digits in reverse order
    }
    cout << "\n"; // Output newline for formatting
}

Sample Output:

 Convert a binary number to octal number:                              
---------------------------------------------                          
 Input a binary number: 1011                                           
 The equivalent octal value of 1011 is : 13

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to convert a binary number to its octal equivalent by grouping bits into sets of three.
Write a C++ program that reads a binary string and converts it to octal by processing the bits in groups.
Write a C++ program to compute the octal representation of a binary number using conversion via decimal intermediary.
Write a C++ program that converts a binary input to octal by parsing the binary string in segments and mapping them.

C++ Code Editor:

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