// CS116 - Summer 1998
// HW2 Problem 1 Solution

#include <iostream.h>

bool even(int num) {
  return((num % 2) == 0);
}

// display checker board with x & o
void displayCheckerBoard(int numRows, int numCols) {

  int currentRow, currentCol;

  // put an 'x' if (row + col) is even otherwise put 'o'
  for (currentRow = 0; currentRow < numRows; currentRow++) {
    for (currentCol = 0; currentCol < numCols; currentCol++) {
      if (even(currentRow + currentCol))
	cout << 'x';
      else
	cout << 'o';
    }
    cout << endl;
  }
}

main () {

  int numRows, numCols;

  // prompt user for number of rows and columns
  cout << "Please enter the number of rows: ";
  cin >> numRows;
  cout << "Please enter the number of columns: ";
  cin >> numCols;
  
  // draw checker board of given dimensions
  displayCheckerBoard(numRows, numCols);

}


// CS116 - Summer 1998
// HW2 Problem 2 Solution

#include <iostream.h>

enum BulbState { On, Off };

main() {

  // an array of 150 light bulbs
  const int ArraySize = 150;
  BulbState bulbArray[ArraySize];
  int index;

  // initialize array to Off
  for (index = 0; index < ArraySize; index++) {
    bulbArray[index] = Off;
  }

  // do switching rounds
  int round;
  for (round = 1; round <= ArraySize; round++) {
    for (index = round - 1; index < ArraySize; index = index + round) {
      bulbArray[index] = (bulbArray[index] == Off) ? On : Off;
    }
  }

  // display all On bulbs
  cout << "Light bulbs that are on at the end: ";
  for (index = 0; index < ArraySize; index++) {
    if (bulbArray[index] == On)
      cout << (index + 1) << " ";
  }
  cout << endl;
}