CS210 Lab: Introduction to Visual C++
Prelab Answers

Prelab Answers:

1. What is the difference between the header file and a program (or source) file?

   A header file has the extension .h and a program (or source) file has the extension .cpp. The header file contains the class declarations for one or more classes, and the program file contains method definitions. The program file includes the header so that it knows about the declarations.

2. Why do we use the scope operator "::" when defining member functions?

   The scope operator :: is used when defining methods. If I have a class called Foo and it has a method called myMethod, when defining the function in the .cpp file, I would call it Foo::myMethod. The scope operator is needed because a .cpp file could contain method definitions for multiple classes, so we need to know for which class each method is being defined.

3. How many levels of protection are there for class members? List them.

   Three: public, private, and protected

4. What is inlining?

   Inlining occurs in C++ when you define methods in the header file. Inlining is typically used only for very short methods. For short routines, C++ can frequently optimize things which are declared inline by inserting the code for the routine directly in the calling function, thus avoiding the large overhead of calling a function. So, it is often to your advantage to inline definitions of short, frequently called functions that don't require use of an external library. For instance:

   		//Color.h
   		class Color
   		{
   		public:
   		   Color();
   		   int getRed() {return _red;}       // inline declaration
      		void setRed(int red) {_red=red;}  // inline declaration
   		   /* same for green and blue */
   		protected:
   		   int _red, _green, _blue;
   		};

5. When shouldn't you inline functions?

   Medium and large-sized functions should not be inlined, even if they are frequently used. Since the the compiler will insert the code for inlined functions wherever the function is called, inlining large functions will increase the size of your program, possibly slowing it down.

6. How do you declare an integer variable?

   int myNumber;

7. How do you declare an integer pointer?

   int* myPtr;

8. How do you assign a value of zero to an integer at the time of declaration?

   int myNumber = 0;

9. What characters are used for commenting code?

   Two ways of commenting are available:

   /* */ comments a block sequence

   // comments single lines