Convert Decimal to Binary in C

In this article, we will learn to write a C program to convert a decimal number into a binary number. The decimal number system uses ten digits from 0 to 9 to represent numbers and the binary number system is a base-2 number system that uses only 0 and 1 to represent numbers.

Algorithm to Convert Decimal Numbers to Binary in C

• Find the remainder by taking the modulus of the given number with 2.
• Store the remainder as a binary digit in an array.
• Update the number by dividing it by 2.
• Repeat these steps till the number is greater than zero.

C Program to Convert Decimal Numbers to Binary

C

// C Program to Convert Decimal Numbers to Binary

#include <stdio.h>

// function to convert decimal to binary
void decToBinary(int n)
{
    // array to store binary number
    int binaryNum[1000];

    // counter for binary array
    int i = 0;
    while (n > 0) {

        // storing remainder in binary array
        binaryNum[i] = n % 2;
        n = n / 2;
        i++;
    }

    // printing binary array in reverse order
    for (int j = i - 1; j >= 0; j--)
        printf("%d", binaryNum[j]);
}

// Driver program to test above function
int main()
{
    int n = 17;
    decToBinary(n);
    return 0;
}

Output

10001

Complexity Analysis

• Time complexity: O(1)
• Auxiliary space: O(1)

Please refer complete article on Program for Decimal to Binary Conversion for more details!