Poj Solution 1001

http://poj.org/problem?id=1001

#include <iostream>
#include <string.h>
using namespace std ;

char R[10] , Num[160] ;
int n , L , Point , i , j , l , k ;
int f[160] , c[160] , A[160] ;
int x , y , z , LA , Lf , w ;

int main() {
    while ( cin >> R >> n ) {
        L = 0 ;
        Point = 0 ;
        for ( k = 0 ; k < strlen(R) ; k ++ )
            if ( R[k] != '0' ) break ;
        for ( i = k ; i < strlen(R) ; i ++ )
            if ( R[i] == '.' ) break ;
        for ( j = strlen(R)-1 ; i < j ; j -- )
            if ( R[j] != '0' ) break ;
        for ( l = k ; l <= j ; l ++ )
            if ( R[l] != '.' )
                Num[++L] = R[l] ;
            else
                Point = j - l ;
        for ( i = 1 ; i < 160 ; i ++ ) {
            f[i] = 0 ;
            c[i] = 0 ;
            A[i] = 0 ;
        }
        f[1] = 1 ;
        Lf = 1 ;
        LA = 0 ;
        for ( j = L ; j >= 1 ; j -- )
            A[++LA] = Num[j]-'0' ;
        for ( i = 1 ; i <= n ; i ++ ) {
            for ( j = 1 ; j <= Lf ; j ++ )
                c[j] = 0 ;
            for ( j = 1 ; j <= LA ; j ++ )
                for ( k = 1 ; k <= Lf ; k ++ ) {
                    x = A[j] * f[k] ;
                    y = x / 10 ;
                    z = x % 10 ;
                    w = j + k - 1 ;
                    c[w] += z ;
                    c[w+1] += (c[w]/10 + y) ;
                    c[w] %= 10 ;
                }
            Lf += LA ;
            while ( c[Lf] == 0 ) Lf -- ;
            for ( j = 1 ; j <= Lf ; j ++ )
                f[j] = c[j] ;
        }
        if ( Lf < Point * n ) {
            cout << "." ;
            for ( i = Point * n ; i > Lf ; i -- )
                cout << "0" ;
        }
        for ( i = Lf ; i >= 1 ; i -- ) {
            if ( i == Point * n ) cout << "." ;
            cout << f[i] ;
        }
        cout << endl ;
    }
    return 0 ;
}