View Code of Problem 101

#include<bits/stdc++.h>
using namespace std;

int main()
{
	string a, b;
	while(cin >> a)
	{
		int n = 3, k = 0;
		int len = a.size();
		for(int i = len - 1; i >= 0; i--)
		{
			if(n == 0)
			{
				b[k++] = ',';
				n = 3;
			} 
			if('0' <= a[i] && a[i] <= '9')
			{
				n--;
				b[k++] = a[i];
			}
			
		}
		for(int j = k - 1; j >= 0; j--)
			cout << b[j];
		cout << endl;
	}
	
		
	return 0;
}