View Code of Problem 101

#include<stdio.h>
#include<string.h>
int main(){
	char s1[100];
	char s2[100];
//	scanf("%s",s1);
//	int len=strlen(s1);
	
	
	while(scanf("%s",s1)!=EOF){
		int len=strlen(s1);
		int k=0;
		int count=0;
		for(int i=len-1;i>=0;i--){//
			if(s1[i]!=','){
				s2[k++]=s1[i];
				count++;
				if(count%3==0){
					s2[k++]=',';
				}
			}
		}//s2里面部是整数 
		for(int i=k-1;i>=0;i--){
			printf("%c",s2[i]);
		}
		printf("\n");
		
		
	}
	
	
	
	
	
	return 0;
}