count the number of ones in a 32

#include
#include
/*no. of 1's in no. of 1's steps*/
int count(unsigned long int n)
{
int count=0;
while(n)
{
   count++;
   n=n&n-1;
}
return count ;
}


/* This is a table which will contain number of ones
corrosponding to number value */
static int bits_in_char [256] ;         

 int bitcount (unsigned int n)
 {
    // works only for 32-bit ints

    return bits_in_char [n         & 0xffu]
        +  bits_in_char [(n >>  8) & 0xffu]
        +  bits_in_char [(n >> 16) & 0xffu]
        +  bits_in_char [(n >> 24) & 0xffu] ;
 }