C++ Problem Set 1

13.cpp

/* Homework Set 1 Problem 13 by Dillon Morse
 * -----------------------------------------
 * An electronics company sells circuit boards at a 40 percent profit. Write a
 * program that will calculate the selling price of a circuit board that costs
 * $12.67. Display the result on the screen.
 */

#include<iostream>
#include<cmath>
using namespace std;

string price(double cost) {
  double selling_price = cost * 1.4;
  string str_price;

  str_price = "$" + to_string(round(selling_price * 100) / 100);
  // This is necessary to remove trailing zeros from the string resulting from
  // the above statement.
  str_price.erase(str_price.find_last_not_of('0') + 1, string::npos);
  
  return str_price;
}

int main() {
  double cost = 12.67;

  cout << price(cost) << '\n';

  // Necessary to prevent warnings from the g++ compiler.
  // 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;
}

5.cpp

/* Homework Set 1, Problem 5 by Dillon Morse
 * -----------------------------------------
 * Write a program that stores the following values in five different
 * variables: 28, 32, 37, 24, and 33. The program should first calculate the
 * sum of these five variables and store the result in a seperate variable
 * named sum. Then, the program should divide the sum variable by 5 to get the
 * average. Display the average on the screen.
 */

#include<iostream>
using namespace std;

const int a = 28;
const int b = 32;
const int c = 37;
const int d = 24;
const int e = 33;

// It is simpler to take the size of the array as an argument than to try and
// find the number of variables in an array pointer.
// The name int_sum prevents conflicts with the variable, sum.
int int_sum(int nums[], int size) {
  // sum is declared as 0 so I can add to it in the for loop without any extra
  // code.
  int sum = 0;

  for(int i = 0; i < size; i++) {
    sum = sum + nums[i];
  }

  return sum;
}

int main() {
  int constants[6] = {a, b, c, d, e};
  // sizeof returns the size of the argument in bytes. So, I am dividing the
  // size of the array constants by the size of a constant stored in the array.
  int size = sizeof(constants) / sizeof(constants[0]);

  int sum = int_sum(constants, size);
  double average = sum / 5;

  cout << average << '\n';

  // Necessary to prevent warnings from the g++ compiler.
  // 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;
}

9.cpp

/* Homework Set 1 Problem 9 by Dillon Morse
 * ----------------------------------------
 * You have been given a job as a programmer on a Cyborg supercomputer. In
 * order to accomplish some calculations, you need to know how many bytes the
 * following data types use: char, int, float, and double. You do not have any
 * manuals, so you can't look this information up. Write a C++ program that
 * will determine the amount of memory used by these types and display the
 * information on the screen.
 */

#include<iostream>
using namespace std;

int main() {
  char character;
  int integer;
  float single_precision_floating_point;
  double double_precision_floating_point;

  string out;

  // sizeof returns the size of a variable in bytes.
  // to_string was added in C++ 11 and is used to convert variables to strings.
  out = to_string(sizeof(character)) + ", " + to_string(sizeof(integer)) +
        ", " + to_string(sizeof(single_precision_floating_point)) + ", " +
        to_string(sizeof(double_precision_floating_point));

  cout << out << '\n';

  // Necessary to prevent warnings from the g++ compiler.
  // 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;
}