Beginners for C++ language

Basics for C++ language:
To write a c++ program, the following details, are need.

1. Command-line:

• It describes what's going on inside a program, so that person looking at the source code does not have a hard time figuring it out.
• Types of comments:

    (i) Single line comments:

     Syntax:

                 /*Statements*/

     Example:

                   /* This is the addition program*/

    (ii) Multiline comments:

     Syntax:

                  //Statement

2.Variables:

• A variable is nothing but it allocates the memory space and holds the values.
• That means every memory of address is difficult to use in the program, conversely, we give that address as a simple user-defined word or character is called variable.

• For example, each user dials the call using a contact name only not use the phone number. i.e. each user needs an easy way to access the phone number to make a call to others.

• Here, the phone number act as a memory address and saved details of contacts called variables(this process happens in CPU).

         Syntax:

                     Data_type variable_name;

         Example:

                     int x, y;

Rules for naming the variables:

• The first character must be an alphabet or an underscore(_).
• No commas or blank spaces are allowed within a variable name.
• No special symbols, an underscore can be used in a variable name.

Scope of variables:

• It implies the availability of variables within the program.
• It is divided into two types.

     (i) Local variable:

• The variables which are defined inside the function block called a local variable.

         Example:

                       void main()

                      {

                              int a,b;//local variable

                              ......

                       }

     (ii) Global variable:

• The variables that are declared before the main() a function is called a global variable.

         Example:

                      int a,b;//Global variable

                      void main()

                     {

                             ......

                      }

3.Data types:

• The data type is the type or kind of data, that is going to process within the program. 
• There are two types of data types.
        *Pre-defined data type
        *User-defined data type

    1. Pre-defined data type:

• The most widely used data types are

  2. User-defined data types:

    (i) Type declaration:

• It is used to allow the user to define an identifier that would represent an existing data type.

         Syntax:

                    typedef data_type identifier;

         Example:

                    typedef int marks;

                    marks m1,m2,m3;

   (ii) Enumerated data type:

• It is used to create user-defined data types i.e. the programmer can create their own data type and define what values the variables of those data types can hold.

         Syntax:

                    enum  enum _name{value 1,value 2, ......,value n};

         Example:

                    enum day{mon,tue,wed,...sun};

4. Input function:

• This function is used to get value from users.

        Syntax:

                    cin>>variable_name;

5.Output function: 

• This function is used to show details on the output screen for user understanding.

         Syntax:

                    cout<<“Statements”;

6.Escape sequence: 

• This is used to align output on the screen.

Example program:

1. /* To print "Welcome to whereisstuff" */
   #include<iostream.h>
   #include<conio.h>//header files
   void main()//main function
   {
   clrscr();
   cout<<"\n \t\"Welcome to whereisstuff.com\" \n";//print function
   cout<<"\n This site\'s used to learning programming languages.";
   getch();
   }

Output:

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