C++ Homework Problem Set 2 solutions

10.cpp

/* Problem Set 2 Question 10 by Dillon Morse
 * -----------------------------------------
 * Write a program that converts Celsius temperatures to Fahrenheit
 * temperatures.
 */

#include<iostream>
using namespace std;

double get_celsius() {
  double temp;

  cout << "What is your temperature in Celsius?" << '\n';
  cin >> temp;

  return temp;
}

double convert_to_fahrenheit(double celsius_temp) {
  double fahrenheit_temp = 9.0 / 5.0 * celsius_temp + 32;
  
  return fahrenheit_temp;
}

int main() {
  double celsius_temp = get_celsius();
  double fahrenheit_temp = convert_to_fahrenheit(celsius_temp);
  
  cout << fahrenheit_temp << " degrees Fahrenheit" << '\n';

  // Necessary to prevent warnings from some compilers.
  // I'm not keeping the program running in a paused state because I am running
  // it from a CLI, so letting it close is most convenient.
  return 0;
}

21.cpp

/* Problem Set 2 Question 21 by Dillon Morse
 * -----------------------------------------
 * For this assignment you will write two programs:
 *
 * Program 1:
 *   Write a program that asks the user to enter five numbers. Use a
 *   floating-point data type to hold the numbers. The program should create a
 *   file and save all five numbers to the file.
 * 
 * Program 2:
 *   Write a program that opens the file created by Program 1, reads the five
 *   numbers, and displays them. The program should also calculate the sum of
 *   the five numbers.
 *
 * For convenience, I will be writing two functions instead of two programs,
 * and calling them both from the main() function.
 */

#include<iostream>
#include<fstream>
#include<cstdlib>
using namespace std;

int program_1() {
  double nums[6];
  ofstream file;
  
  cout << "Please enter 5 numbers, seperated by carriage returns" << '\n';
  cin >> nums[0] >> nums[1] >> nums[2] >> nums[3] >> nums[4];

  file.open("file.txt");
  file << nums[0] << '\n' <<
          nums[1] << '\n' <<
          nums[2] << '\n' <<
          nums[3] << '\n' <<
          nums[4] << '\n';
  file.close();

  return 0;
}

int program_2() {
  ifstream file;
  string line;
  double nums[6];
  // Initializing i and sum as 0 allows me to add to them in loops without any
  // extra code.
  int i = 0;
  double sum = 0;

  file.open("file.txt");
  while(file >> nums[i]) {
    i = i + 1;
  }
  file.close();

  cout << "Numbers: " <<
          nums[0] << ", " <<
          nums[1] << ", " <<
          nums[2] << ", " <<
          nums[3] << ", " <<
          nums[4] << '\n';

  cout << "Sum: ";
  // sizeof returns the size of its argument in bytes. This allows me to find
  // the number of variables in the array by dividing the size of the array by
  // the size of a variable stored in the array.
  for(i = 0; i < sizeof(nums) / sizeof(nums[0]); i = i + 1) {
    sum = sum + nums[i];
  }

  cout << sum << '\n';

  return 0;
}

int main() {
  cout << "Program 1:" << '\n';
  program_1();

  cout << '\n' << "Program 2:" << '\n';
  program_2();

  // Necessary to prevent warnings from some compilers.
  // I'm not keeping the program running in a paused state because I am running
  // it from a CLI, so letting it close is most convenient.
  return 0;
}

7.cpp

/* Problem Set 2 Question 7 by Dillon Morse
 * ----------------------------------------
 * A bag of cookies holds 40 cookies. The calorie information on the bag claims
 * that there are 10 "servings" in the bag and that a servimg equals 300
 * calories. Write a program that asks the user to input how many cookies he or
 * she actually ate and then reports how many total calories were consumed.
 */

#include<iostream>
using namespace std;

int how_many() {
  int cookies;

  cout << "How many cookies did you consume?" << '\n';
  cin >> cookies;

  return cookies;
}

double total_calories(int cookies) {
  double cookies_per_serving = 40 / 10;
  double calories_per_serving = 300;
  double total = cookies / cookies_per_serving * calories_per_serving;

  return total;
}

int main() {
  int cookies = how_many();
  double total = total_calories(cookies);

  cout << "You consumed " << total << " calories." << '\n';

  // Necessary to prevent warnings from some compilers.
  // I'm not keeping the program running in a paused state because I am running
  // it from a CLI, so letting it close is most convenient.
  return 0;
}