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

Last update on April 07 2025 12:59:17 (UTC/GMT +8 hours)

73. Binary to Decimal Conversion

Write a C++ program to convert a binary number to a decimal number.

Visual Presentation:

C++ Exercises: Convert a binary number to decimal 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
{
    long binaryNumber, decimalNumber = 0, j = 1, remainder; // Declare variables for binary and decimal numbers, remainder, and a multiplier

    cout << "\n\n Convert a binary number to decimal number:\n"; // Display message prompting for binary to decimal 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

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

    cout << " The decimal number: " << decimalNumber << "\n"; // Display the resulting decimal number
}

Sample Output:

Convert a  binary number to decimal number:                           
-----------------------------------------------                        
 Input a binary number: 1011                                           
 The decimal number: 11

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to convert a binary number (as a string) to its decimal equivalent using iterative multiplication.
Write a C++ program that reads an 8-bit binary number and calculates its decimal value using the power of 2.
Write a C++ program to compute the decimal conversion of a binary input by processing each digit from right to left.
Write a C++ program that accepts a binary string, converts it to decimal using a loop, and prints the result.

C++ Code Editor:

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