UVa 202

Repeating Decimals.cpp

#include <stdio.h>
#include <iostream>
#include <string>
#include <map>

using namespace std;

int main()
{
	auto a = 0, b = 0;
	while (~scanf("%d%d", &a, &b))
	{
		printf("%d/%d = %d.", a, b, a / b);
		auto remainder = a % b;

		auto cycle = string{};
		auto remainderHistory = map<int, int>();
		while (true)
		{
			if (remainderHistory.find(remainder) != remainderHistory.end())
			{
				cycle.insert(remainderHistory[remainder], "(");
				cycle.append(")");
				break;
			}

			remainderHistory[remainder] = cycle.size();
			remainder *= 10;
			cycle.append(to_string(remainder / b));
			remainder = remainder % b;
		}

		auto cycleLength = cycle.size()- remainderHistory[remainder] - 2;
		if (cycleLength >= 51)
		{
			cycle = cycle.substr(remainderHistory[remainder], 51) + "...)";
		}

		cout << cycle << endl;
		printf("   %d = number of digits in repeating cycle\n\n", cycleLength);
	}
	return 0;
}