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DATA TYPES

Data types are the means to identify the type of data and associated operations.

### FUNDAMENTAL DATA TYPE

Apart from the considered data types there is one more most important type i.e, void.

#### Void

It is used for an empty set of values and as a return type for the non-returning function.It is also a fundamental data type.

#### String

It is used as the data type for characters which include space.

As , string name = â€œJames Bondâ€ ;

### DERIVED DATA TYPE

We will discuss these types further in detail in coming lessons.

#### Bade Kaam ki baat (BKKB 1):-

Floating point numbers have 2 advantages over integers

1. They can represent values between integers.
2. They can represent a much greater range of values.

But floating point operation are usually slower than integer operation.

#### Bade Kaam ki baat (BKKB 2):

Double data type has 2 advantages over floating point

1. They can represent values between integers.
2. They can represent a much greater range of values.

But double occupies double memory than float. The type double is larger and slower than type float.

## VARIABLES

Variables are the named storage locations, whose values can be manipulated during program run.
For example- To store names, roll no,marks of students we need storage locations that to named in order to distinguish them easily.

### DECLARATION OF VARIABLES

Creating a variable of a particular data type is known as declaration of variable.

Syntax

`type name; //where type represents data type and name is the variable name.`

#### INITIALIZATION OF VARIABLES

A Variable with declared first value is said to be intialized variable.

Following are the forms of initialization:

```  int num =12;
int num(12);
int num= int(12);
In all cases num got itâ€™s initial value as 12. ```

#### DYNAMIC INITIALIZATION:-

It is defined as initialization of variables at run time using expressions at place of value.

``` For example-
float avg;
avg=sum/count;         ```

Letâ€™s see a program with use of data types and variables.

```//program to accept a number and print its cube.
#include<iostream.h>
#include<conio.h>
Void main()                          //data type for main function is void i.e, main is a non-returning function.
{  float b,c ;                         //creating two variable of float type
cout<<â€enter the number\nâ€;
cin>>b;
c= b*b*b;                           //dynamic initialization
cout<<â€\nThe cube ofâ€<<b<<â€isâ€<<c;
getch();                            //program doesnâ€™t return any value
}```

OUTPUT

```enter the number
6
The cube of 6 is 216```

#### FLOW OF STATEMENTS

In a program statements can be executed sequentially, selectively or iteratively.

#### SEQUENTIALLY

It means statements are executing in sequence. This represent default flow of control.

#### SELECTIVELY

It means statements are executing based on a condition test. If the condition evaluates to be true a set of a statement is followed, otherwise, another set of a statement is followed.

There are two types of selection statements:

1. If statement
2. Switch statement

#### ITERATIVELY

According to it repetitive execution of statements take place depending upon a condition test. Execution is continued till the time condition is matched. It is also known as looping.

C++ provide three types of loops:

1. For loop
2. While loop
3. Do-while loop

We will study them in next articles.

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