void main()
{
// using a bit of random here.
srand(time(nullptr)); //initialize random seed based on time
// Where will this object live? Is this a good choice? Why or why not?
TestObject anObject = TestObject(30);
// Name differences between pointers and references
TestObject *anotherObject = new TestObject(2); //error: new returns a pointer-> '*'
// When should we use pointers, references and values? why?
TestObject &referenceToAnObject = anObject; //error: no &
TestObject &referenceToAnotherObject = *anotherObject; //error original adress called with '*'
TestObject* pointerToAnObject = &anObject; //error: for pointer,adress of obj. is needed with &
TestObject* pointerToAnotherObject = &referenceToAnotherObject; // error fix: for pointer, adress of Obj. is needed with '&'
// Testing if the correct strings are being printed.
referenceToAnotherObject.printAllStrings();
std::cout << "The Following should be the same as above: " << std::endl;
pointerToAnotherObject->printAllStrings();
std::cout << std::endl << "total number of strings:" << std::endl;
int& TotalElementNumber = sumTheElements(referenceToAnObject.elementCount(), referenceToAnotherObject.elementCount());
std::cout << TotalElementNumber << std::endl;
std::cout << "Do calculations in another scope and display the same value again inside that scope: " << std::endl;
{
//this isn't really doing anything, just for testing purposes
int ignoreMe = 20;
ignoreMe *= TotalElementNumber;
std::cout << TotalElementNumber << std::endl;
}
std::cout << "And again outside the scope: " << std::endl;
std::cout << TotalElementNumber << std::endl;
delete anotherObject;
//cant delete objects with stack
//delete pointerToAnObject;
//delete pointerToAnotherObject;
}
void main()
{
// using a bit of random here.
srand(time(nullptr)); //initialize random seed based on time
// Where will this object live? Is this a good choice? Why or why not?
// This Object will be on the Stack. Not so good, because we have a pointer to it later
// its not so bad here, but normally it is bad to have a pointer to something on the stack
// because if the scope ends and the pointer continues to exist, it can point to something useless
TestObject anObject = TestObject(30);
// Name differences between pointers and references
// Pointer can be changed, references not after initialization. pointer can be null, refer. not. References can be used like the object and need no dereference
TestObject* anotherObject = new TestObject(2);
// When should we use pointers, references and values? why?
// pointers for optional parameters
// references for any none-elemental datatypes
// values for small (32/64Bit) datatype and no change
//reference is initialized with variable name, not adress
TestObject& referenceToAnObject = anObject;
// same here, so we have to dereference the pointer "anotherObject" first
TestObject& referenceToAnotherObject = *anotherObject;
// pointer is initialized with adress, so we have to get ADRESS from "anObject"
TestObject* pointerToAnObject = &anObject;
// same here, although referenceToAnotherObject is a reference(basically a adress too)
// it is used like the object itself, so we need to GET the ADRESS here too
TestObject* pointerToAnotherObject = &referenceToAnotherObject;
// Testing if the correct strings are being printed.
referenceToAnotherObject.printAllStrings();
std::cout << "The Following should be the same as above: " << std::endl;
pointerToAnotherObject->printAllStrings();
std::cout << std::endl << "total number of strings:" << std::endl;
int& TotalElementNumber = sumTheElements(referenceToAnObject.elementCount(), referenceToAnotherObject.elementCount());
std::cout << TotalElementNumber << std::endl;
std::cout << "Do calculations in another scope and display the same value again inside that scope: " << std::endl;
{
//this isn't really doing anything, just for testing purposes
int ignoreMe = 20;
ignoreMe *= TotalElementNumber;
std::cout << TotalElementNumber << std::endl;
}
std::cout << "And again outside the scope: " << std::endl;
std::cout << TotalElementNumber << std::endl;
delete anotherObject;
// these pointers have not been initialized with new, so cannot be deleted
//delete pointerToAnObject;
//delete pointerToAnotherObject;
}
int main()
{
// using a bit of random here.
srand(time(nullptr)); //initialize random seed based on time
// Where will this object live? Is this a good choice? Why or why not?
// stack. the stack/heap choice does not really matter here, because the object itself allocates the bulk of its space on the heap.
TestObject anObject = TestObject(30);
// Name differences between pointers and references
// # References:
// * cannot point to unknown space
// * cannot be changed after definition
// * behave like the variable they reference most of the time
// * immutable
// # Pointers:
// * can point to whatever
// * can be changed whenever
// * behave like a pointer
// * mutable
TestObject anotherObject = TestObject(2);
// When should we use pointers, references and values? why?
// use the value if it is very small, and changes in the function are not required out of it
// use a pointer if the object does exist at definition time, or when a parameter may be null
// use a reference whenever you can
TestObject &referenceToAnObject = anObject;
TestObject &referenceToAnotherObject = anotherObject;
TestObject* pointerToAnObject = &anObject;
TestObject* pointerToAnotherObject = &referenceToAnotherObject;
// Testing if the correct strings are being printed.
referenceToAnotherObject.printAllStrings();
std::cout << "The Following should be the same as above: " << std::endl;
pointerToAnotherObject->printAllStrings();
std::cout << std::endl << "total number of strings:" << std::endl;
const int& TotalElementNumber = sumTheElements(referenceToAnObject.elementCount(), referenceToAnotherObject.elementCount());
std::cout << TotalElementNumber << std::endl;
std::cout << "Do calculations in another scope and display the same value again inside that scope: " << std::endl;
{
//this isn't really doing anything, just for testing purposes
int ignoreMe = 20;
ignoreMe *= TotalElementNumber;
std::cout << TotalElementNumber << std::endl;
}
std::cout << "And again outside the scope: " << std::endl;
std::cout << TotalElementNumber << std::endl;
// everything is on the stack, nothing needs to be deleted
//delete pointerToAnObject;
//delete pointerToAnotherObject;
return 0;
}