View Code of Problem 101

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main() {
	char a[1000],b[1000],c[1000];
	while(scanf("%s",&a)!=EOF){
		int j=0,i,k=0;
		for(i=0;i<strlen(a);i++){
			if(a[i]>='0' && a[i]<='9'){
				b[j++]=a[i];
			}
		}
		int count=0;
		for(i=j-1;i>=0;i--){
			c[k++]=b[i];
			count++;
			if(count%3==0 && count!=0 && i!=0){
				c[k++]=',';
			}
		}
		for(i=k-1;i>=0;i--){
			printf("%c",c[i]);
		}
		printf("\n");
	}
}