The programs to convert decimal to binary have been shown here.

## 1. C Program to convert decimal to binary

Code has been copied
/*************************************
alphabetacoder.com
C program to convert decimal to binary
**************************************/

#include <stdio.h>

int main() {
// declare variables
long num;
int bin[31] = {0};
int i, n = 0;

// take input
printf("Enter the number in decimal: ");
scanf("%ld", & num);

// convert the number in binary
//store the result in an array
// binary number would be stored
// in reverse order
while (num > 0) {
bin[n] = num % 2;
n++;
num = num / 2;
}

// display the number in binary
printf("Binary: ");
for (i = n - 1; i >= 0; i--) {
printf("%d", bin[i]);
}

// new line
printf("\n");

return 0;
}


Output

#### Case 1:

Enter the number in decimal: 77

Binary: 1001101

#### Case 2:

Enter the number in decimal: 9

Binary: 1001

## 2. C Program to convert decimal to binary using recursion

Code has been copied
/****************************
alphabetacoder.com
C program to convert decimal
to binary using recursion
*****************************/

#include <stdio.h>

// function to display
// decimal to binary
void decimal_to_binary(long num) {
if (num > 1) {
// call the function
decimal_to_binary(num / 2);
}
// display binary digit
printf("%ld", num % 2);
}

int main() {
// declare variables
long num;

// take input
printf("Enter the number in decimal: ");
scanf("%ld", & num);

printf("Binary: ");
// call function to display
// the decimal number in binary
// display the number in binary
decimal_to_binary(num);

// new line
printf("\n");

return 0;
}


Output

#### Case 1:

Enter the number in decimal: 77

Binary: 1001101

#### Case 2:

Enter the number in decimal: 9

Binary: 1001