C program to convert decimal to binary

In this post, you will learn how to convert a decimal into an equivalent binary number using the C programming language. Here, we have mentioned three ways to convert a decimal to a binary number.

A decimal number is a base-10 number system. It ranges from 0 to 9, i.e., 0,1,2,3,4,5,6,7,8,9. Any combination of digits is a decimal number, such as 61, 22, 912, 0, 5 etc. The main advantages of the decimal number system are that it is easy-to-read, used by humans, and easy to manipulate.

A binary number consists of two numbers, 0s and 1s. It is expressed in the base-2 numeral system or binary numeral system. As the computer only understands binary language, that is 0 or 1, all inputs given to a computer are decoded by it into series of 0's or 1's to process it further. Any combination of 0 and 1 is a binary number, such as 1011, 100, 101011, 111011 etc.

Decimal to binary in C using for loop

The given program converts decimal to binary using a for loop. First, we divided the number by 2 using the modulus operator and stored the remainder in an array. Next, we divide the number by 2 through the division operator and repeat the same process until the number is greater than zero.

/* C Program to convert decimal to binary */

#include <stdio.h>
int main()
{
    int a[10], num, i, j;
    printf("\nPlease enter the number : ");
    scanf("%d", &num);

    for(i = 0; num > 0; i++)
    {
        a[i] = num % 2;
        num = num / 2;
    }

    printf("\nBinary number of the given number : ");
    for(j = i - 1; j >= 0; j--)  {
        printf(" %d ", a[j]);
    }
    printf("\n");
    return 0;
}

Please enter the number : 25

Binary number of the given number =   1  1  0  0  1

Please enter the number : 52

Binary number of the given number :  1  1  0  1  0  0

Decimal to binary in C using while loop

In the given C program, we have used the while loop to convert decimal to binary.

#include <stdio.h>

int main()
{
    int a[10], num, i = 1, j;
    printf("\nPlease enter the number : ");
    scanf("%d", &num);

    while(num != 0)
    {
        a[i++] = num % 2;
        num = num / 2;
    }

    printf("\nBinary number of the given number : ");
    for(j = i - 1; j > 0; j--)  {
        printf(" %d ", a[j]);
    }
    return 0;
}

Please enter the number : 35

Binary number of the given number :  1  0  0  0  1  1

ease enter the number : 22

Binary number of the given number :  1  0  1  1  0

Decimal to binary in C using function and for loop

In this program, we have created a user-defined function Decimal_to_Binary() and used for loop and the Bitwise AND Operator to convert a decimal to a binary number. The programs takes decimal number (entered by user) as input and converts it into a binary number using the function Decimal_to_Binary().

/* C Program to convert decimal to binary */

#include <stdio.h>

void Decimal_to_Binary(int num)
{
    int y;
    for(int x = 31; y >= 0; x--)
    {
        y = num >> x;

        if(y & 1)
            printf("1");
        else
            printf("0");
    }
}
int main()
{
    int num;

    printf("\n Please enter the number : ");
    scanf("%d", &num);

    Decimal_to_Binary(num);

    return 0;
}

Please enter the number : 19
00000000000000000000000000010011

Decimal to binary in C using function and while loop

In the given C program, we have created a user-defined function decimal_to_binary() and used a while loop and Bitwise AND Operator to convert a decimal to a binary number. This program takes decimal number (entered by the user) as input and converts it into a binary number using the function decimal_to_binary().

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

long decimal_to_binary(int decimalnum)
{
    long binarynum = 0;
    int rem, temp = 1;

    while (decimalnum!=0)
    {
        rem = decimalnum%2;
        decimalnum = decimalnum / 2;
        binarynum = binarynum + rem*temp;
        temp = temp * 10;
    }
    return binarynum;
}

int main()
{
    int decimalnum;
    printf("Enter a Decimal Number: ");
    scanf("%d", &decimalnum);
    printf("Equivalent Binary Number is: %ld", decimal_to_binary(decimalnum));
    return 0;
}

Enter a Decimal Number: 67
Equivalent Binary Number is: 1000011

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