CS 10 SI Lab Session 3 - Roulette Exercise

main.cpp

#include <iostream>
#include <cstdlib>

using namespace std;

int main() {
  // What would happen if we replaced time(0) here with a number, like 2?
  srand(time(0));

  // The two question marks below mean that you should figure out the correct
  // types for each of the variables.

  // If the user bets on a number, this will be the user's choice, otherwise
  // it will be 0.
  ? user_num = 0;

  // This will be true if the user bet on red.
  ? user_red;

  // Hook the user into playing our devious game.
  cout << "Search your pockets! Place your bets! Pray to your deities! Let's "
          "play roulette!\n"
          "You sir! Yes you. Come here.\n"
          "Would you like to place a bet on a number or color? ";

  string user_input;
  cin >> user_input;

  if (user_input == "number") {
    cout << "\nWhich number sir (1-35)? ";

    cin >> user_num;
  } else if (user_input == "color") {
    cout << "\nWhich color sir? ";

    string user_color_input;
    cin >> user_color_input;

    // Notice the use of a boolean expression here. What will user_red hold if
    // the user enters yellow?
    user_red = user_color_input == "red";
  }

  // Randomly choose a number that our virtual ball has landed on.
  // The question mark here means that you should replace it with an expression
  // that would make sense here.
  int result_num = ?;

  // We are going to pretend that odd numbers are red and even numbers are black
  // despite roulette having more complicated rules than that.
  // Notice I'm using the modulo operator to detect whether the number is even
  // or odd, how does this work?
  bool result_red = result_num % 2 == 0;

  cout << "\nThe ball landed on " << result_num;

  // If we just printed out the value of result_red here, what would be
  // displayed?
  if (result_red) {
    cout << " red. ";
  } else {
    cout << " black. ";
  }

  // Here we figure out if the user won. Determine what should replace the
  // questions marks in the below statements. Hint: They will be boolean
  // expressions.
  bool user_won;
  if (user_num == 0) {
    user_won = ?;
  } else {
    user_won = ?;
  }

  if (user_won){
    cout << "Which means you win! Congratulations sir!\n";
  } else {
    cout << "Which means you lose! I'm sorry sir!\n";
  }

  return 0;
}

solution.cpp

#include <iostream>
#include <cstdlib>

using namespace std;

int main() {
  // What would happen if we replaced time(0) here with a number, like 2?
  srand(time(0));

  // The two question marks below mean that you should figure out the correct
  // types for each of the variables.

  // If the user bets on a number, this will be the user's choice, otherwise
  // it will be 0.
  int user_num = 0;

  // This will be true if the user bet on red.
  bool user_red;

  // Hook the user into playing our devious game.
  cout << "Search your pockets! Place your bets! Pray to your deities! Let's "
          "play roulette!\n"
          "You sir! Yes you. Come here.\n"
          "Would you like to place a bet on a number or color? ";

  string user_input;
  cin >> user_input;

  if (user_input == "number") {
    cout << "\nWhich number sir (1-35)? ";

    cin >> user_num;
  } else if (user_input == "color") {
    cout << "\nWhich color sir? ";

    string user_color_input;
    cin >> user_color_input;

    // Notice the use of a boolean expression here. What will user_red hold if
    // the user enters yellow?
    user_red = user_color_input == "red";
  }

  // Randomly choose a number that our virtual ball has landed on.
  // The question mark here means that you should replace it with an expression
  // that would make sense here.
  int result_num = rand() % 35 + 1;

  // We are going to pretend that odd numbers are red and even numbers are black
  // despite roulette having more complicated rules than that.
  // Notice I'm using the modulo operator to detect whether the number is even
  // or odd, how does this work?
  bool result_red = result_num % 2 == 0;

  cout << "\nThe ball landed on " << result_num;

  // If we just printed out the value of result_red here, what would be
  // displayed?
  if (result_red) {
    cout << " red. ";
  } else {
    cout << " black. ";
  }

  // Here we figure out if the user won. Determine what should replace the
  // questions marks in the below statements. Hint: They will be boolean
  // expressions.
  bool user_won;
  if (user_num == 0) {
    user_won = user_red == result_red;
  } else {
    user_won = user_num == result_num;
  }

  if (user_won){
    cout << "Which means you win! Congratulations sir!\n";
  } else {
    cout << "Which means you lose! I'm sorry sir!\n";
  }

  return 0;
}