Informatics3-2024/Practical5

A lap jelenlegi, 2024. március 26., 07:39-kori változata

Exercises

Open a new project for each exercise or a new file if you're in the command line.

From this point onward use .cpp file extensions!

Complex class from the lecture

Execute the code from the lecture:

#include<iostream>
#include<cmath>
 
using namespace std;
 
 
class Complex {
private:
  float re;
  float im;
public:
  Complex();
  Complex(const Complex& other);
  Complex(float r);
  Complex(float r, float i);
 
  Complex add(Complex other);
  Complex times(Complex other);
  float abs();
 
  void print();
 
  ~Complex();
};
 
Complex::Complex() {
  re = 0;
  im = 0;
}
 
Complex::Complex(const Complex& other) {
  re = other.re;
  im = other.im;
}
 
Complex::Complex(float r) {
  re = r;
  im = 0;
}
 
Complex::Complex(float r, float i) {
  re = r;
  im = i;
}
 
Complex Complex::add(Complex other) {
  return Complex(this->re + other.re, this->im + other.im);
}
 
Complex Complex::times(Complex other) {
  float real = this->re * other.re - this->im * other.im;
  float imag = this->re * other.im + this->im * other.re;
  return Complex(real, imag);
}
 
float Complex::abs() {
  return sqrt(this->re * this->re + this->im * this->im);
}
 
void Complex::print() {
  cout << re << " + " << im << "i" << endl;
}
 
Complex::~Complex() {
}
 
int main(void) {
  Complex a;
  Complex b = Complex(1,2);
  Complex c = a.times(b);
 
  a.print();
  b.print();
  c.print();
 
  (b.add(c)).print();
 
  cout << b.abs() << endl;
 
  return 0;
}

Rectangle

Write a Rectangle class!

• Constructed with the length of its 2 edges.
• Methods to get its area and perimeter.
• It should have a scale method that can scale the rectangle (both edge lengths are multiplied by the given number).
• It should be copyable, like so:

Rectangle a(2, 5);
Rectangle b(a);

Back to the Complex

Let's check back on the Complex class. Feed its code to pythontutor and check when each method/constructor is called.

String class

Write a String class that will ease our use of C strings.

• The default constructor should create an empty string.
• We should be able to construct it from a C string. The constructor should look like this:

String(const char* s);

• We should be able to retrieve its length.
• Make a print method that prints the string using cout.
• Make a method that concatenates two Strings.

Linked list

Implement the previously used linked list with classes. The list should store floats and have the following features:

• default constructor: empty list
• copy constructor
• constructor that builds the list from an array
• destructor
• append: new element at the end
• insert: new element at the given index
• size: returns the number of elements stored
• in: true/false whether the given value is stored in the list or not
• index: retrieves the element at the given index
• remove: removes an element at the given index
• where: returns the first index where the given value can be found, returns -1 if the value isn't in the list