General CPP Notes

Encapsulation

Interface in the .h file. Implementation in the .cpp file.

Remember include guards in the .h file!

#ifndef NAME_H
#define NAME_H

#endif

Memory Management

Stack grows downward, starting at highest going to lowest. Read up the stack from lowest to highest memory address. Heap grows up. Allocated with new keyword. Never automatically reclaimed.

For each new call, there should be a delete call. Remember to set variable to NULL after deleting.

Special case for deleting arrays: delete [] arr;

Pointers

A pointer variable holds a memory address.

Size of a pointer is 8 bytes.

Warning: int* ptr, notPtr creates one int* and one int

int val = 5;
int* ptr = &val; // ptr points to val

Reference Variables

& operator. Variable that refers to memory of existing variable. Only way to name memory on heap. Never creates its own memory.

Overloading Operators

bool Class::operator<(const Class &var);

Constructors

Automatic Default Constructor -- Provided if no other copy constructors defined. "Soft" copy of all variables (copies memory addresses, not value).

Copy Constructor -- Returns deep copy of object

Sphere(const Sphere& a) {
	memberVar_ = a.memberVar_;
}

Assignment Operator (=) called when assigning new value to existing object. Needs a self-destruct check. Copy Constructor called when creating new object from existing object.

Rule of Three

If any of these three are needed, all three must be defined.

1. Copy Constructor
2. Destructor
3. Assignment operator (=)

Passing Parameters

1. Pass by Value -- func(Sphere a)
   • Slow, makes a new copy of the entire object.
   • Does not modify original.
   • Always valid object passed in.
2. Pass by Pointer -- func(Sphere* a)
   • Faster than PbV, only copies the memory address.
   • Modifies original.
   • NULL pointer potentially passed in.
3. Pass by Reference -- func(Sphere& a)
   • Fastest, no copying at all.
   • Allows direct manipulation of data.
   • Always valid object passed in.

Const

1. Function parameters -- int func(const Sphere a)

   • Guarantees value passed in will not be changed.

2. Class function declarations -- int func(Sphere a) const;

   • Guaranteed not to modify the state of the class.

Inheritance

class Derived: public Base {}

1. If you need a custom constructor to construct Base object, Initializer List required to construct Derived class.
2. Derived inherits public functions of Base directly, and protected data indirectly (may have to use getters). (?)

• Constructors called from Base to Derived.

• Destructors called from Derived to Base.

• virtual keyword allows derived classes to override function behavior.

• virtual Class::func() = 0 is pure virtual. Requires derived class to implement function.

• Constructors can not be virtual.

• Destructor in Base should be virtual.

Templates

• Allow functions and classes to operate with generic class types
• Checked at compile time

Iterators

• Allow us to traverse data regardless of underlying structure.
• Declared in public block of class.

Functors

• Objects that can be called like a function.
• If it has an overloaded () operator, likely a functor.
• Functors can track state (?)