C Programming Examples Tutorial Index

C Number Programs

Converting binary numbers to decimal is a fundamental aspect of computer science and programming. This tutorial will guide you through writing a C program that efficiently converts a binary number to its equivalent decimal representation.

What is Binary to Decimal Conversion?

Binary-to-decimal conversion involves translating a number from the binary system (base 2), which utilizes digits 0 and 1, to the decimal system (base 10), which employs digits from 0 to 9. This conversion is essential as computers operate in binary, while humans commonly use decimals.

Algorithm to Convert Binary to Decimal

  1. Initialize Variables: Declare variables to store the binary number and decimal equivalent.
  2. Input Binary Number: Prompt the user to enter a binary number. Use the scanf() function to take input from the user.
  3. Conversion Process: Implement a loop that repeatedly extracts the last digit of the binary number, multiplies it by the appropriate power of 2, and adds it to the decimal equivalent variable. After each iteration, update the binary number by removing the extracted digit.
  4. Output Decimal Number: Display the calculated decimal number using the printf() function.

Code Example

Here's a C program that implements the binary-to-decimal conversion algorithm:

#include <stdio.h>
#include <math.h>

int main() {
    long long binary;
    int decimal = 0, i = 0, remainder;

    // Take user input for the binary number
    printf("Enter a binary number: ");
    scanf("%lld", &binary);

    // Conversion process
    while (binary != 0) {
        remainder = binary % 10;
        binary /= 10;
        decimal += remainder * pow(2, i);

    // Display the decimal number
    printf("Decimal equivalent: %d\n", decimal);

    return 0;

Program Output:

For example, if you input the binary number 1101, the program will convert and display the decimal equivalent as 13.

Enter a binary number: 1101
Decimal equivalent: 13


Developing a C program to convert binary to decimal numbers provides a practical understanding of number systems and fundamental computer operations. This tutorial enables you to create a program that accurately performs this conversion, enhancing your grasp of binary and decimal systems and their role in computer programming.

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