In a C program, first step is to initialize the graphics drivers on the computer. This is done using the initgraph() method provided in graphics.h library. In the next few pages we will discuss graphics.h library in more details. Important functions in graphic.h library will be discussed in details and samples programs will be provided to show the power of C programming language especially for graphic programming developing graphical user interfaces.
A constructor is a special method that is created when the object is created or defined. This particular method holds the same name as that of the object and it initializes the instance of the object whenever that object is created. The constructor also usually holds the initialization of the different declared member variables of its object.
A pointer is a variable that represents the location of a data item, such as a variable or an array element. Pointers are used frequently in C, as they have a number of useful applications. For example, pointers can be used to pass information back and forth between a function and its reference point. Pointers provide a way to return multiple data items from a function via function arguments to
be specified as arguments to a given function.
A class is an organisation of data and functions which operate on them. Data structures are called data members and the functions are called member functions, The combination of data members and member functions constitute a data object or simply an object.
C programs are executed in a sequence, but we can control the execution of program by using any control mechanism by which we can compare things and come to a decision. This involves using some operations called Relational Operators, conditional statements called if-else and loops. We have fundamental operators to compare two values.