CC150 17.5

17_5.cpp

/* CC150 17.5 */
// the game of master mind (RGBY)

#include <iostream>
#define N 4

class Result {
public:
	Result() : hits(0), phits(0) {}
	Result(int h, int p) : hits(h), phits(p) {}
	int hits;
	int phits;
};

int colormap(char color) { // translate color to index
	switch (color) {
	case 'R':
		return 0;
	case 'G':
		return 1;
	case 'B':
		return 2;
	case 'Y':
		return 3;
	default:
		return -1; // indicate invalid entry
	}
}

Result guessResult(char sol[], char guess[])
{
	int hits = 0, phits = 0;
	int solCount[N] = { 0, 0, 0, 0 };
	int guessCount[N] = { 0, 0, 0, 0 };
	for (int i = 0; i != N; ++i) { // count hits and occurrence of non-hits
		if (sol[i] == guess[i])
			++hits;
		else {
			++solCount[colormap(sol[i])];
			++guessCount[colormap(guess[i])];
		}
	}
	for (int i = 0; i != N; ++i)
		phits += solCount[i] < guessCount[i] ? solCount[i] : guessCount[i];
	return Result(hits, phits);
}

bool readGuess(char guess[])
{
	bool valid = true;
	for (int i = 0; i != N; ++i) {
		std::cin >> guess[i];
		if (colormap(guess[i]) == -1) {
			std::cerr << "Invalid input!" << std::endl;
			valid = false; // keep read cin rather than break; otherwise need to clear cin buffer
		}
	}
	return valid;
}

int main()
{
	char sol[N];
	std::cout << "Solution: ";
	while (!readGuess(sol)); // store solution
	char guess[N];
	while (1) {
		std::cout << "Guess: ";
		while (!readGuess(guess)); // read guess
		Result result = guessResult(sol, guess);
		std::cout << "Hits: " << result.hits << "; ";
		std::cout << "Pseudo-hits: " << result.phits << std::endl;
		if (result.hits == N)
			break;
	}
	return 0;
}