Uva160.c

#include<stdio.h>
#include<math.h>
#define ERROR 0.000000001


int main()
{
    int N;
    while( scanf( "%d", &N ) != EOF && N != 0 )
    {
        int i;
        int prime_count[105] = {0};
        for( i = N ; i >= 2 ; i-- )
        {
            int temp = i;
            int j;
            int sqrt_i = (int)( sqrt( (double)temp ) + ERROR );
            for( j = 2 ; j <= sqrt_i ; j++ )
                while( !(temp % j) )
                {
                    prime_count[j]++;
                    temp /= j;
                }
            if( temp > 1 )
                prime_count[temp]++;
        }
        printf( "%3d! =", N );
        int count = 0;
        for( i = 2 ; i <= N ; i++ )
        {
            if( prime_count[i] )
            {
                if( !(count % 15) && count != 0 )
                    printf( "\n      " );
                count++;

                printf( "%3d", prime_count[i] );
            }
        }
        printf( "\n" );
    }
    return 0;
}