// CS116 - Summer 1998
// HW1 Problem 1 Solution

#include <iostream.h>

main() {

  int first, second, smaller;

  // prompt user for two integers and read them in
  cout << "Please enter two integers: ";
  cin >> first >> second;

  // display the smaller one
  if (first < second) {
    smaller = first;
  } else {
    smaller = second;
  }

  // display smaller integer
  cout << "The smaller integer is " << smaller << "." << endl;
}


// CS116 - Summer 1998
// HW1 Problem 2 Solution

#include <iostream.h>

main() {

  int low, high;

  // prompt user for low and high and read them in
  cout << "Please enter two integers, the first not larger than the second: ";
  cin >> low >> high;

  if (low <= high) {

    // input is good, sum up all integers from low to high
    int current, sum = 0;
    for (current = low; current <= high; current++) {
      sum = sum + current;
    }
    // display sum
    cout << "The sum of all integers from " << low
	 << " to " << high << " is " << sum << "." << endl;

  } else {

    // bad input, report error and finish
    cout << "sum:  ** error: first number larger than second. Exiting."
	 << endl;

  }
}


// CS116 - Summer 1998
// HW1 Problem 3 Solution

#include <iostream.h>

main() {

  int input, posCount = 0, negCount = 0;
  bool quit = false;

  while (!quit) {

    // prompt user for input and read it in
    cout << "Please enter an integer (0 to quit): ";
    cin >> input;

    if (input == 0) {
      // quitting
      quit = true;

    } else {
      // increment appropriate count
      if (input < 0)
	posCount++;
      else
	negCount++;

    }
  }

  // display summary
  cout << "Summary:" << endl
       << posCount << " of the numbers were positive," << endl
       << negCount << " of the numbers were negative." << endl;

}


// CS116 - Summer 1998
// HW1 Problem 4 Solution

#include <iostream.h>

main() {

  // search range is 1 to 1024, user answers y/n
  int low = 1, high = 1024, mid;
  char answer;

  // ask user to choose a number in the range
  cout << "Please choose an integer between 1 and 1024..." << endl;

  // do binary search until range has one element only
  while (low != high) {

    // compute *integer* midpoint and ask question
    // (mid is immediately left of the "true" middle
    mid = (low + high - 1) / 2;
    cout << "Is your number bigger than " << mid << " ? (y/n) ";
    cin >> answer;

    // divide range in half by adjustment of proper boundary
    if (answer == 'y') {
      low = mid + 1;
    } else {
      high = mid;
    }
  }

  // display found answer
  cout << "Your number is " << low << "." << endl;
}