编程之美，寻找1的个数

/***
*编程之美：1的个数
*给定一个十进制正整数，写下从1开始，到N的所有正整数，然后数一下其中出现所有给定“1” 的个数
***/
#include
using namespace std;
int main(){
    int ibit=1;
    long N;
    long icount=0;
    int ihighnumber=0;
    int icurrnumber=0;
    int ilowernumber=0;
    cout<<"请输入N：";
    while(cin>>N){
        icount=0;
        ibit=1;
        ihighnumber=0;
        icurrnumber=0;
        ilowernumber=0;
        while(N/ibit>0){
           ihighnumber=N/(ibit*10);
           icurrnumber=(N/ibit)%10;
           ilowernumber=N%ibit;
           switch(icurrnumber){
                case 0:{
                     icount+=ihighnumber*ibit;
                     break;
                }
                case 1:{
                     icount+=ihighnumber*ibit+ilowernumber+1;
                     break;
                }
                default:{
                     icount+=(ihighnumber+1)*ibit;
                     break;
                }                
           }   
           ibit*=10;                        
        }
        cout<     }
    return 0;   
}