C++ Programming Code Examples
C++ > Beginners Lab Assignments Code Examples
Class that imitates the functionality of the basic data type
/* Class that imitates the functionality of the basic data type */
# include<iostream.h>
#include<conio.h>
class Int
{
int var;
public :
/* Here we try to overcome the problem of carbage value by
initializing the value by 0 */
Int()
{
var =0;
}
// Overloaded Constructor
Int(int a )
{
var = a;
}
int add( Int b) // Note : Int , not int
{
var+=b.var; /* For ex. if the user enters
a.add(b);
then result will be
a = a + b; */
return(var);
}
void disp() //again, Int
{
cout<<var;
}
}; // Do not forget this ;
void main(void)
{
clrscr();
Int a = 12;
Int b = 10;
a.disp();
cout<<"
a+b = "<<a.add(b);
getch();
}
The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program. The getch() function does not accept any parameter from the user. It returns the ASCII value of the key pressed by the user as an input.
As the name already suggests, these operators help in assigning values to variables. These operators help us in allocating a particular value to the operands. The main simple assignment operator is '='. We have to be sure that both the left and right sides of the operator must have the same data type. We have different levels of operators. Assignment operators are used to assign the value, variable and function to another variable. Assignment operators in C are some of the C Programming Operator, which are useful to assign the values to the declared variables. Let's discuss the various types of the assignment operators such as =, +=, -=, /=, *= and %=. The following table lists the assignment operators supported by the C language:
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
It is a predefined function in "conio.h" (console input output header file) used to clear the console screen. It is a predefined function, by using this function we can clear the data from console (Monitor). Using of clrscr() is always optional but it should be place after variable or function declaration only. It is often used at the beginning of the program (mostly after variable declaration but not necessarily) so that the console is clear for our output.
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
In C++, constructor is a special method which is invoked automatically at the time of object creation. It is used to initialize the data members of new object generally. The constructor in C++ has the same name as class or structure. Constructors are special class functions which performs initialization of every object. The Compiler calls the Constructor whenever an object is created. Constructors initialize values to object members after storage is allocated to the object. Whereas, Destructor on the other hand is used to destroy the class object. • Default Constructor: A constructor which has no argument is known as default constructor. It is invoked at the time of creating object.
As we know function overloading is one of the core feature of the object oriented languages. We can use the same name of the functions; whose parameter sets are different. Here we will see how to overload the constructors of C++ classes. The constructor overloading has few important concepts. • Overloaded constructors must have the same name and different number of arguments. • The constructor is called based on the number and types of the arguments are passed. • We have to pass the argument while creating objects, otherwise the constructor cannot understand which constructor will be called.
The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (<<) to display the output on a console. On most program environments, the standard output by default is the screen, and the C++ stream object defined to access it is cout. The "c" in cout refers to "character" and "out" means "output". Hence cout means "character output". The cout object is used along with the insertion operator << in order to display a stream of characters.
The main purpose of C++ programming is to add object orientation to the C programming language and classes are the central feature of C++ that supports object-oriented programming and are often called user-defined types. A class is used to specify the form of an object and it combines data representation and methods for manipulating that data into one neat package. The data and functions within a class are called members of the class.
Increment ++ and decrements -- operator are overloaded in best possible way, increase the value of a data member by 1 if "++" operator operates on an object and 'decrease' value of
