Binary converter in C

 #include <stdio.h>

#include <math.h>

long decimalToBinary(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", decimalToBinary(decimalnum));

    return 0;

}