Define a copy method void copy(const vector* other) and add it/incorporate it into the vector class definition.

Question

Review the entire code. Define a copy method void copy(const vector* other) and add it/incorporate it into the vector class definition (i.e. the file you will submit should have everything our vector class has + new method copy). The copy method is given a pointer to the other vector object and should copy all the information from that vector to this vector. Note that you cannot guarantee that this and the other vector are the exact same sizes.

#include <iostream>

class vector {

int sz; // the size

double * elem; // a pointer to the elements

public:

vector(int s): sz(s), elem(new double[s]) { // constructor

for (int i{0}; i < s; ++i) elem[i] = 0;

}

~vector() { // destructor

delete[] elem;

}

double get(int n) const {return elem[n];}; // access:read

void set(int n, double v) {elem[n] = v;} // access:write

int size() const {return sz;} // the current size

// a member function that would display the values of the vector object

void display() {

for (int i{ 0 }; i < sz; ++i)

std::cout << elem[i] << " ";

}

/* a member function resize(int newSz) that resizes the vector to the new size,

preserving all the existing elements */

void resize(int newSz) {

double* tmp = new double[newSz]; // allocate new space

for (int i{0}; i < sz; ++i) // copy the existing values

tmp[i] = elem[i];

for (int i{sz}; i < newSz; ++i) // the rest of the places are filled with 0s

tmp[i] = 0;

delete[] elem; // release the space pointed to by elem

elem = tmp; // reassign the elem pointer to the newly allocated array

sz = newSz; // update the size

}

};

// not "frending" it with vector class this time

// overloading the output operator<< to be used with objects of this class

std::ostream & operator<<(std::ostream & out, const vector & v) {

for (int i{0}; i < v.size(); ++i)

out << v.get(i) << " ";

return out;

}

int main() {

vector a(10); // create a vector of 10 elements

// filling it with values 1, 3, 5, ..., 19

for(int i{0}; i<10; ++i)

a.set(i, 2 * i + 1);

// using overloaded output stream operator

std::cout << a << std::endl;

//changing the size to 20 elements

a.resize(20);

std::cout << "\nThe element of the vector after resizing: \n" << a << std::endl;

}

Answer 1

You've already been given the beginning of the function,

void copy(const vector* other) {

and the rest is:

[put your logic here, including calling the 'other->size()'; the other->get(), a number of them, and the

instructions remind you to not forget to resize - make sure you do it in the right place]

}

Fortunately, 'resize' already exists. But resize() has a bug. What happens if the new vector is smaller than the existing one?