C++ errors with releasing Dynamic memory [closed] - c++

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Error - *** error for object 0x7ffeefbff360: pointer being freed was not allocated.
I understand its better to use vectors, but our prof wants us to use it this way.
My unwrap function is giving me errors where I want to release the memory, also when I want to print the pattern using the for loop in the display function it gives me a garbage value out of memory instead of printing out the pattern itself. I tested using cout in the wrap function and it works there but not in my display function.
bool wrap(Gift& theGift){
if (theGift.m_wrap == nullptr) {
cout << "Wrapping gifts..." << endl;
do {
cout << "Enter the number of wrapping layers for the Gift: ";
cin >> theGift.m_wrapLayers;
}while ((theGift.m_wrapLayers <= 0) && cout << "Layers at minimum must be 1, try again." << endl);
theGift.m_wrap = new Wrapping[theGift.m_wrapLayers];
char buffer[100];
int patternLength;
for (int i = 0; i < theGift.m_wrapLayers; i++) {
cout << "Enter wrapping pattern #" << i + 1 << ": ";
cin >> buffer;
patternLength = (unsigned)strlen(buffer);
theGift.m_wrap[i].m_pattern = new char[patternLength + 1];
theGift.m_wrap[i].m_pattern = buffer;
cout << theGift.m_wrap[i].m_pattern << endl;
}
return true;
}else {
cout << "Gift is already wrapped!" << endl;
return false;
}
}
bool unwrap(Gift& theGift){
if (theGift.m_wrap != nullptr) {
cout << "Gift being unwrapped." << endl;
for (int i = 0; i < theGift.m_wrapLayers; i++) {
delete[] theGift.m_wrap[i].m_pattern;
theGift.m_wrap[i].m_pattern = nullptr;
}
delete[] theGift.m_wrap;
theGift.m_wrap = nullptr;
return true;
}else{
cout << "Gift isn't wrapped! Cannot unwrap." << endl;
return false;
}
}
void display(Gift& theGift){
cout << "Gift Details: " << endl;
cout << " Description: " << theGift.m_description << endl;
cout << " Price: " << theGift.m_price << endl;
cout << " Units: " << theGift.m_units << endl;
cout << "Wrap Layers: " << theGift.m_wrapLayers << endl;
for (int i = 0 ; i < theGift.m_wrapLayers; i++) {
cout << "Wrap #" << i + 1 << " ->" << theGift.m_wrap[i].m_pattern << endl;
}
}

Answer 1

Error - *** error for object 0x7ffeefbff360: pointer being freed was not allocated.
in wrap :
char buffer[100];
...
theGift.m_wrap[i].m_pattern = buffer;
you save in the in-out parameter theGift a pointer to the local array buffer (and you have a memory leak for the lost of the allocation done in theGift.m_wrap[i].m_pattern = new char[patternLength + 1]; just before)
and later in unwrap :
delete[] theGift.m_wrap[i].m_pattern;
you try to delete that invalid pointer.
In fact in wrap rather than :
theGift.m_wrap[i].m_pattern = new char[patternLength + 1];
theGift.m_wrap[i].m_pattern = buffer;
you wanted to do :
theGift.m_wrap[i].m_pattern = new char[patternLength + 1];
strcpy(theGift.m_wrap[i].m_pattern, buffer);
Note you can also use std::string for m_pattern rather than array of char, and a std::vector<Wrapping>for m_wrap rather than an array of Wrapping. That simplify a lot, no new nor delete