accessing the member of a class of pointer array of another class - c++

Question

I'm trying to figure out how I can or why I can't access the member of this class. First I'll show you what works so you know what I'm thinking, then I'll show you what I can't seem to do.
What I can do is this: I have a class with a member. I make an pointer array of that class and make NEW pieces of it (through loop) and that's fine and all. I can also make another class with a similar array and even make NEW instances of that as well and initialize them, but when I try to access them, I have problems.
This code almost works fine:
#include <iostream>
using namespace std;
class testClass{
public:
int number;
};
class testPoint{
public:
testClass testInstance;
testClass *testclassArray[5];
void makeArray();
void setToI();
};
void testPoint::makeArray(){
for (int i = 0; i < 5; i++){
testclassArray[i] = new testClass;
}
}
void testPoint::setToI(){
for (int i = 0; i < 5; i++){
(*testclassArray[i]).number = i;
}
}
int main(void){
testPoint firstTestPoint;
firstTestPoint.makeArray();
firstTestPoint.setToI();
// EXCEPT FOR THIS LINE this is where I have problems
cout << firstTestPoint.(*testclassArray[0]).number << endl;
return 0;
}
I know this should work becuase this works
int main(void){
testPoint firstInstance;
firstInstance.testInstance.number = 3;
cout << firstInstance.testInstance.number << endl;
// and this works
return 0;
}
and this works
int main(void){
testClass *testPointer[5];
for (int i = 0; i < 5; i++){
testPointer[i] = new testClass;
(*testPointer[i]).number = i;
}
cout << (*testPointer[0]).number << endl;
return 0;
}
so why can't I access the members on the cout function the same way?

Answer 1

The following is invalid syntax:
cout << firstTestPoint.(*testclassArray[0]).number << endl;
The most common way to write what you are trying to accomplish is:
cout << firstTestPoint.testclassArray[0]->number << endl;
But, if you prefer, you can also write:
cout << (*firstTestPoint.testclassArray[0]).number << endl;
(The second way is far less common.)
The . operator is used to access members of direct objects, e.g. a.member where a might be declared as struct A a;. The -> operator is used to access members of indirect objects (aka pointers to objects), e.g. b->member where b might be declared as struct B* b = new B();.

Answer 2

You are dereferencing the variable in an incorrect way.
Try doing
cout << firstTestPoint.testclassArray[0]->number << endl;
instead.
In the same way the second attempt, where it works for you, could also have been written:
out << testPointer[0]->number << endl;

Answer 3

Try using this code:
cout << firstTestPoint.testclassArray[0]->number << endl;