Programming Features Of C++

Programming Features of C++

To understand the features used in a C++ Program, let us consider a example to print a string.

#include<iostream>      //header file

using namespace std;

int main( )

{

         cout<<"C++ Program";       //C++ statement

         return 0;

}                                                  //end of program

In the above program, we can see various features used in a program. These features as follows:-

Comments:-

• Comments includes the lines which we want to ignore or do not want to consider in our program.
• Comment may start anywhere in the line.
• The double slash // comment is used for a single line comment.
• For multiline comments /*___*/ is used.

Output Operator:-

• In the above program, the ouput statement is,        

                  cout<<"C++ Program";

• Here, "cout" is an identifier which is a predefined object that represents the standard output stream in C++.
• The standard output stream represents the screen.
• Operator << is called the insertion or put to operator.
• It inserts the contents of the variable on its right to the object on its left.

The iostream file:-

• A C++ program typically contains the pre-processor directory statements at the beginning.
• All C++ Programs begin with a #include directive that includes the specified header file contents into the main program.
• The header file iostream should be included at the beginning of all programs that use input/output statements.
• Using the appropriate header files depending on the contents of the program and implementation.

Namespace:-

• The namespace concept was introduced by ANSI C++ committee.
• For using the identifier defined in the namespace scope using a directive files is must.
• std is the namespace where ANSI C++ standard class libraries are defined.

Return type of main( ):-

• In C++, main( ) returns an integer type value to the operating system. Hence, every main( ) in C++ should end with a return(0) statement, otherwise an error might occur.
• The default return type for all functions in C++ is int.

For understanding more features, we are taking another program, which is as follows:

#include<iostream>

using namespace std;

int main( )

{

       int no1, no2, sum, average;

       cout<<"Enter two numbers";

       cin>>no1;

       cin>>no2;

       sum=no1+no2;

       average=sum/2;

       cout<<"sum="<<sum<<endl;

       cout<<"average="<<average<<endl;

       return 0;

}

We can see that there are some other features too, they are as follows:

Variables:-

• In our program, we have used four variables which are no1, no2, sum, average.
• Before the variables are used in program, they must be declared.

Input Operator:-

• Here, input statements are

               cin>>no1;

               cin>>no2;

• It is an input statment and causes the program to wait for the user to type in a number.
• cin is also an identifier which is a predefined object in C++ that represents the standard input stream. 
• The operator >> is known as extraction or get from operator.
• It takes the value from the keyboard and assigns it to the  variable on its right.

Cascading of input/output operators:-

• In the above program,we have two statements as,

       cout<<"sum="<<sum<<endl;

       cout<<"average="<<average<<endl;

• Here, the insertion operator << is repeatedly used to display the result.
• First it sends the string "sum=" and "average=" to the cout and then it sends the value of sum and average.
• Atlast, it sends the newline character, so that the next output will be in the newline.
• Hence, multiple use of << or >> in one statement is called Cascading of input/output operator.