CODEWITHSUNDEEP
c++classoperator-overloadingoverloadingdynamic-arrays
Cid
Cid

Reputation: 17

Why is the overloading operator "=" not working properly on my class for Dynamic Arrays? C++

I'm trying to work with dynamic arrays. When I try to overload the "=" operator it does not work. When debugging the file it doesn't execute the void function to overload the operator.

#include <iostream>
using namespace std;

class cppArray {
public:
    cppArray(int size);
    ~cppArray();
    int read(int index);
    void write(int content, int index);
    void operator=(cppArray& s);
    int search(int target);
    int size();
private:
    int* myArray;
    int arraySize;
};

cppArray::cppArray(int size) {
    myArray = new int[size];
    arraySize = size;
}

//delete the memory space assigned to myArray 
cppArray::~cppArray() {
    delete[] myArray;
    myArray = 0;
}

int cppArray::read(int index) {
    if (index < arraySize) {
        return myArray[index];
    }
    else {
        cout << "Out of range" << endl;
        exit(1);
    }
}

Here I'm trying to copy the content of the original array to an auxiliar one, and then redefine the size of the original array so I can add more content to the original array

void cppArray::write(int content, int index) {
    if (index < arraySize) {
        myArray[index] = content;
    }
    else {
        cppArray auxArray(arraySize);
        auxArray.myArray = myArray;
        delete[] myArray;
        arraySize = index + 1;
        myArray = new int[arraySize];
        myArray = auxArray.myArray;
        myArray[index] = content;
    }
}

I'm pretty sure this is wrong, but I can't figure out a way to overload it correctly

void cppArray::operator=(cppArray& s) {
    delete[] s.myArray;
    s.myArray = new int[arraySize];
    for (int i = 0; i < arraySize; i++)
    {
        myArray[i] = s.myArray[i];
    }
}

int cppArray::size() {
    return arraySize;
}

int main(int argc, char** argv) {
    cppArray dsArray(3);

    dsArray.write(1, 0);
    dsArray.write(2, 1);
    dsArray.write(3, 2);
    dsArray.write(4, 3);

    for (int i = 0; i < dsArray.size(); i++) {
        cout << dsArray.read(i) << "\t";
    }

    cout << endl;

    return 0;
}```

Upvotes: 0

Views: 59

Answers (1)

Yksisarvinen
Yksisarvinen

Reputation: 22354

Your implementation is almost correct, but you delete the wrong array. You should only modify *this object, and not s. Also, you should follow conventions, or people will be very surprised when using your class.

Here's corrected version:

//return *this - a very expected convention
cppArray& cppArray::operator=(const cppArray& s) {
// Make sure s is not modified ^^^^
    if (this == &s) {
        return *this; //protection against self writing, things would get bad if you did that
    }

    arraySize = s.arraySize; //copy size first
    delete[] myArray; //delete array from this object
    myArray = new int[arraySize]; //recreate array
    for (int i = 0; i < arraySize; i++)
    {
        myArray[i] = s.myArray[i]; //no changes here
    }

    return *this;
}

Upvotes: 3

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