POJ 2719

#include<iostream>
#include<stdio.h>
using namespace std;
int dight[9];
int _pow(int m,int n);
int main(){
    //freopen("test.txt","r",stdin);
    int i;
    int num;
    dight[0] = 0;
    dight[1] = 1;
    for(i = 2; i < 9 ; i++)
    {
        dight[i] = _pow(10,i-1) + dight[i-1] + 8*dight[i-1];
    }
    while(cin>>num){
        if(num == 0)
            break;
        int j;
        int k = 0;
        int temp;
        temp = num;
        int sum = 0;
        while(temp)
        {
            j = temp%10;
            temp /= 10;
            if(j > 4)
            {
                sum += _pow(10,k);
                sum += dight[k]*(j-1);
            }
            else
                sum += dight[k]*j;
            k++;
        }
    cout<<num<<": "<<num-sum<<endl;
    }
    system("pause");
}
int _pow(int m,int n)
{
    if(n == 0)
        return 1;
    else if(1 == n)
        return m;
    else
        return m*_pow(m,n-1);
}