编程之美-2.4 1的数目

package code.beauty.fungame;

public class CountOne {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int n =1111111110;
//		count1InAllInt(n);
Sum1s(n);
}
private static int count1InAInt(int n){
int num = 0;
while(n!=0){
num += (n%10 == 1)? 1:0;
n=n/10;
}
return num;
}
private static void count1InAllInt(int n){
int num = 0;
for(int i = 1; i<=n ; i++ ){
num += count1InAInt(i);
}
System.out.println("count1InAllInt:"+num);
}

private static int Sum1s(int n){
int sum = 0;
int iFactor = 1;
int i_hight = 0;
int i_low = 0;
int i_Curr = 0;
while(n/iFactor!=0){

i_hight = n/(iFactor*10);
i_low = n%iFactor;
i_Curr = (n/iFactor)%10;
switch(i_Curr){
case 0 :
sum +=(i_hight*iFactor);
break;
case 1 :
sum +=(i_hight*iFactor + i_low+1);
break;
default :
sum +=((i_hight+1)*iFactor);
}
iFactor *=10;
}
System.out.println("Sum1s:"+sum);
return sum;
}

}