WRITE A FUNCTION TO CALCULATE THE BINARY EQUIVALENT OF A NUMBER IN DECIMAL BASE

#include<conio.h>
#include<stdio.h>
#include<math.h>
void main()
{
int binary(int*,int);
int num,a[10],i;
clrscr();
printf("enter the number\n");
scanf("%d",&num);
i=binary(a,num);
i--;
printf("the binary equivalennt of %d is ",num);
for(;i>=0;i--)
printf("%d",a[i]);
getch();
}

int binary(int*p,int n)
{
int i;
for(i=0;n>=1;i++)
{
*(p+i)=n%2;
n=n/2;
}
return(i);
}