Runtime error when vector in class constructor? - c++

Question

Hi I am unable to use a vector in the constructor. I'm trying to parse a vector that contains [x,y] coordinates into the object.
The errors I've gotten are runtime error and bad alloc.
Is there something I'm missing?
Do I have to use dynamic memory allocation?
ShapeTwoD(Parent Class of Child Class Square):
class ShapeTwoD {
protected:
string name;
bool containsWarpSpace;
vector<string> vect;
private:
public:
ShapeTwoD() {}
ShapeTwoD(string name, bool containsWarpSpace, vector<string> vect) {
this->vect = vect;
this->name = name;
this->containsWarpSpace = containsWarpSpace;
}
Class Square that is a child of ShapeTwoD:
class Square : public ShapeTwoD {
public:
Square() : ShapeTwoD(name, containsWarpSpace, vect) {
this->vect = vect;
this->name = name;
this->containsWarpSpace = containsWarpSpace;
}
~Square() {}
};
Main Function:
vector<string> temp;
string merge;
for (int i = 0; i < 4; i++) {
cout << "Please enter x-ordinate of pt " << i + 1 << " :";
cin >> x;
cout << "Please enter y-ordinate of pt " << i + 1 << " :";
cin >> y;
merge = x + ", " + y;
temp.push_back(merge);
}
Square obj;
obj.setName(shape);
obj.setCoord(temp);
if (specialtype == "ws") {
obj.setContainsWarpSpace(true);
}
else if (specialtype == "ns") {
obj.setContainsWarpSpace(false);
}
myvector.push_back(obj);
temp.clear();
cout << "\nRecords successfully stored. Going back to main menu ...\n"
<< endl;
}

Answer 1

In your Square constructor, you are not passing any arguments:
Square() : ShapeTwoD(name,containsWarpSpace,vect){
^^^^^^^^^^^^^^^^^^^^^^^^^^^
That means that the name, containsWarpSpace and vect refer to the parent class fields, which haven't been initialized yet (because that's the job of the ShapeTwoD constructor). So you are taking uninitialized variables and passing them into the constructor to initialize those same variables. More explicitly what you are doing is
Square():ShapeTwoD(this->ShapeTwoD::name,
this->ShapeTwoD::containsWarpSpace, this->ShapeTwoD::vect){
You should either pass them in:
Square(string name, bool containsWarpSpace, vector<string> vect)
:ShapeTwoD(name,containsWarpSpace,vect) {
or pass a sensible default:
Square() : ShapeTwoD("", false, {}) {

Answer 2

The problem is:
merge = x + ", " + y;
The ", " is a const char[3] (a null terminated character array). As an array, it decays to a pointer (const char *), which is offset by x+y as a result of summation with int. The resultant pointer refers to an unknown memory location. Next null byte is not guaranteed to reside in accessible address range; even if such byte is in an accessible address, the output would not be meaningful; because you are triggering UB.
You can fix it like this:
merge = std::to_string(x) + ", " + std::to_string(y);
Regards,
FM.