C++ Overloading operator >> (input) doesn't change original - c++

Question

I'm trying to build a custom dictionary class with custom string and definition classes. While trying to overload the >> (input) I get some kind of a problem. when the function ends the dictionary sent to it doesn't change. attaching the code:
This is the overloading:
istream& operator>>(istream& ip, Dictionary& var) {
Definition temp;
ip >> temp;
var += temp;
return ip;
}
and some other functions used in it:
Dictionary& Dictionary::operator+=(Definition& input) {
if (!checkCopy(input))
{
Definition** temp;
temp = new Definition*[numWords + 1];
for (int i = 0; i < numWords; i++)
{
temp[i] = book[i];
}
numWords++;
temp[numWords - 1] = &input;
delete[] book;
book = temp;
}
return *this;
}
Dictionary::Dictionary(Dictionary& input) {
*this = input;
}
Dictionary& Dictionary::operator=(Dictionary& input) {
if (numWords != 0)
delete[] book;
book = new Definition*[input.numWords];
for (int i = 0; i < input.numWords; i++)
{
*this += *input.book[i];
}
return *this;
}
And the class itself:
class Dictionary
{
private:
int numWords = 0;
Definition** book;
public:
Dictionary();
~Dictionary();
Dictionary(Dictionary&);
bool operator==(Dictionary&) const;
Dictionary& operator=(Definition&);
Dictionary& operator=(Dictionary&);
friend ostream& operator<<(ostream&, const Dictionary&);
friend istream& operator>>(istream&, Dictionary&);
Dictionary& operator-=(int);
Dictionary& operator+=(Definition&);
bool checkCopy(Definition&);
Definition& operator[](int); //left side brackets for input
Definition operator[](int) const; //right side brackets for output
};
EDIT: here is also the overloading operator for definition input:
istream& operator>>(istream& ip, Definition& var)
{
cout << "Please enter a word: " << endl;
ip >> var.word;
cout << "Please enter the number of definitions for this word: " << endl;
int idx;
cin >> idx;
while (idx<0)
{
cout << "Error: number of definitions not possible. Please Try again: " << endl;
cin.clear();
cin.ignore(INT_MAX, '\n');
cin >> idx;
}
cin.clear();
cin.ignore(INT_MAX, '\n');
String* temp = new String[idx];
for (int i = 0; i < idx; i++) {
cout << "Please enter the " << i + 1 << "th definition: " << endl;
cin >> temp[i];
var += temp[i];
}
var.sortDefinition();
return ip;
}
Help is indeed needed.

Answer 1

You should really stick to std::vector and other collection types rather than juggling around with pointers and new/delete as you do here.
In your operator+= function you're copying the address of a temporary variable into your array:
temp[numWords - 1] = &input;
Once the calling function operator>> ends, this pointer is less than worthless, because the original object (Definition temp;) does not exist any longer. Therefore the behaviour of that code is undefined!
You might get around this by defining a copy c'tor for Definition and then changing above line to:
*temp[numWords - 1] = input;
Also in your assignment operator you're making use of the operator+= function. However, your numWords member is not set appropriately at this time, so operator+= will likely do the wrong thing. So add a line to the assignment operator like this:
if (numWords != 0)
{
delete[] book;
numWords = 0; // add this line
}

Answer 2

There were 2 problems:
what Alexander said about the temporary variable. changed it to:
Dictionary& Dictionary::operator+=(Definition& input) {
if (!checkCopy(input))
{
Definition** temp;
temp = new Definition*[numWords + 1];
temp[0] = new Definition[numWords];
for (int i = 0; i < numWords; i++)
{
temp[i] = book[i];
}
temp[0][numWords] = input;
delete[] book;
book = temp;
numWords++;
}
return *this;
}
The second was that in the Definition class when I tried to access the number of definitions in an object that wasn't created due to the double pointer:
Definition** temp;
temp = new Definition*[numWords + 1];
So I changed it so it won't access it but first build it.
Thanks for the help Alexander!