pig

#include <cstdlib>
#include <ctime>
#include <iostream>
#include <fstream>

const char FILENAME[] = "output.txt";
const int DIE_SIZE = 100;

int g_holdAt = 0,
    g_simulations = 0;
double g_pigProb = 0,
    g_probs[DIE_SIZE] = {};

void PrintTable(std::ostream& ostrm) {
    //Formatting stuff.
    ostrm.setf(std::ios::fixed);
    ostrm.setf(std::ios::showpoint);
    ostrm.precision(6);

    //Print table Header.
    ostrm << "\nScore\tEstimated Probability" << std::endl;

    //Print probability for 0.
    ostrm << 0 << "\t" << g_pigProb << std::endl;

    //Print other probabilities.
    for (int i = 0; i < DIE_SIZE; ++i) {
        ostrm << g_holdAt + i << "\t" << g_probs[i] << std::endl;
    }
}

int main() {
    //Seed.
    srand(333);

    //Get hold value and simulations from user.
    std::cout << "What value should we hold at? ";
    std::cin >> g_holdAt;
    std::cout << "Hold-at-N turn simulations? ";
    std::cin >> g_simulations;

    //Accumulate sums.
    for (int i = 0; i < g_simulations; ++i){
        int sum = 0;
        while (sum < g_holdAt) {
            int rollVal = rand() % DIE_SIZE + 1;
            if (rollVal == 1) {
                sum = 0;
                break;
            }
            sum += rollVal;
        }
        if (sum == 0) {
            g_pigProb++;
        }
        else {
            g_probs[sum - g_holdAt]++;
        }
    }

    //Calc probabilities.
    g_pigProb /= g_simulations;
    for (int i = 0; i < DIE_SIZE; ++i) {
        g_probs[i] /= g_simulations;
    }

    //Print table to console.
    PrintTable(std::cout);

    //Print table to file.
    std::ofstream fout;
    fout.open(FILENAME);
    PrintTable(fout);
    fout.close();

    return 0;
}