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MADE BY:-RAFIYA SIRIN

XI-B


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DATA TYPES

Data types are means to identify the type of

data and associated operations of handling

it. C++ provides a predefined set of data

types for handling the data it uses. Whenvariables are declared of a particular data

type then the variable becomes the place

where the data is stored and data types is

the type of value(data) stored by thatvariable. Data can be of may types such as

character, integer, real etc. since the data to

be dealt with are of may types, a

programming language must provide


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DATA TYPES

FUNDAMENTAL DATATYPES

USER DEFINED DATATYPES

DATA TYPE MODIFIERS

DERIVED DATA TYPES


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FUNDAMENTAL DATA TYPES

INTEGER

CHARACTER

DOUBLE

VOID

FLOAT

FUNDAMENTAL DATA TYPES ARE

THOSE THAT ARE NOT

COMPOSED OF OTHER DATATYPES


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Integers are whole numbers with a machinedependent range of values. A good programminglanguage as to support the programmer bygiving a control on a range of numbers and

storage space. C has 3 classes of integerstorage namely short int, int and long int. All ofthese data types have signed and unsignedforms. A short int requires half the space than

normal integer values. Unsigned numbers arealways positive and consume all the bits for themagnitude of the number. The long andunsigned integers are used to declare a longerrange of values.


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CHARACTER DATA TYPE

It can store any member of the C++implementation's basic character set.If a character from this set is stored in

a character variable, its value isequivalent to the integer code of thatcharacter. Character data type is oftencalled as integer data type because

the memory implementation of chardata type is in terms of the numbercode.


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FLOAT DATA TYPE

A number having fractional part is a floating- point number. Anidentifier declared as float becomes a floating-point variable and canhold floating-point numbers. floating point variables represent real

numbers. They have two advantages over integer data types:-

1: they can represent values between integers.

2: they can represent a much greater range of values.

they have one disadvantage also, that is their operations are usually

slower.


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The data type double is also used for handling

floating-point numbers. But it is treated as a

distinct data type because, it occupies twice as

much memory as type float, and stores floating-

point numbers with much larger range and

precision. It is slower that type float.


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It specifies an empty set of values. It is

used as the return type for functions that

do not return a value. No object of typevoid may be declared. It is used when

program or calculation does not require

any value but the syntax needs it.


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DATA TYPE MODIFIERS

INTEGER TYPEMODIFIERS

CHARACTER TYPEMODIFIERS

FLOATING-POINTMODIFIERS

THEY CHANGE SOME

PROPERTIES OF THE

DATA TYPE


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INTEGER TYPE MODIFIERS

C++ offers three types of integer data type:-

1:- short integer- at least two bytes.

2:- int integer at least as big as short.

3:- long integer-at least four bytes.

the prefix signed makes the integer type hold

negative values also. Unsigned makes the integernot to hold negative values.


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TYPE APPROXIMATESIZE

MINIMAL RANGE

SHORT 2 -32768 to 32767

UNSIGNEDSHORT

2 0 to 65,535

SIGNED SHORT 2 Same as short

INT 2 -32768 to 32767

UNSIGNED INT 2 0 to 65,535

SIGNED INT 2 Same as int

LONG 4 -2,147,483,648 TO 2,147,483,647

UNSIGNEDLONG

4 0 to 4,294,967,295

SIGNED LONG 4 Same as long


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CHARACTER TYPE

MODIFIER The char can also be signed or unsigned. unlike

int,char is not signed or unsigned by default. It is latermodified to best fit the type to the hardwareproperties.

TYPE APPROXIMATE SIZE MINIMAL RANGE

CHAR 1 -128 to 127

UNSIGNED CHAR 1 0 to 255

SIGNED CHAR 1 Same as char


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FLOATING POINT TYPE

MODIFIERS

There are three floating-point types: float, double, and long

double. These types represent minimum allowable range of

types.

Note:-dont use commas in numeric values assigned tovariables.

TYPE APPROXIMA

TE SIZE

DIGITS

OFPRECISIO

N

FLOAT 4 7

LONG

DOUBLE

8 15

LONG 10 19


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Name Description Size* Range*

char Character or small integer. 1bytesigned: -128 to 127

unsigned: 0 to 255

short int (short) Short Integer. 2bytessigned: -32768 to 32767

unsigned: 0 to 65535

int Integer. 4bytes

signed: -2147483648 to

2147483647


long int (long) Long integer. 4bytes

signed: -2147483648 to

2147483647


float Floating point number. 4bytes +/- 3.4e +/- 38 (~7 digits)

doubleDouble precision floating point

number.8bytes +/- 1.7e +/- 308 (~15 digits)

long doubleLong double precision floating

point number.8bytes +/- 1.7e +/- 308 (~15 digits)


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DERIVED DATA TYPES

ARRAYS

POINTERS

REFERENCES

CONSTANTS

FUNCTIONS


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ARRAYSAn array is a series of elements of the same type placed in

contiguous memory locations that can be individuallyreferenced by adding an index to a unique identifier.

That means that, for example, we can store 5 values of type intin an array without having to declare 5 different variables, eachone with a different identifier. Instead of that, using an array wecan store 5 different values of the same type, int for example,with a unique identifier.

Like a regular variable, an array must be declared before it isused. A typical declaration for an array in C++ is:type name [elements];

NOTE: The elements field within brackets [ ] which represents thenumber of elements the array is going to hold, must be a constantvalue, since arrays are blocks of non-dynamic memory whose size mustbe determined before execution.


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VALID OPERATIONS WITH ARRAYS:-

billy[0] = a;

billy[a] = 75;

b = billy [a+2];

billy[billy[a]] = billy[2] + 5;

PROGRAM:-

// arrays example#include

using namespace std;

int billy [] = {16, 2, 77, 40, 12071};

int n, result=0;

int main () OUTPUT:- 12206

{

for ( n=0 ; n


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FUNCTIONS:-Function groups a number of program statements into a unit and gives it a

name. This unit can be invoked from other parts of a program. Acomputer program cannot handle all the tasks by it self. Instead itsrequests other program like entities called functions in C to get itstasks done. A function is a self contained block of statements thatperform a coherent task of same kind.

The name of the function is unique in a C Program and is Global. It meansthat a function can be accessed from any location with in a C Program.We pass information to the function called arguments specified whenthe function is called. And the function either returns some value to thepoint it was called from or returns nothing.

We can divide a long C program into small blocks which can perform a

certain task. A function is a self contained block of statements thatperform a coherent task of same kind.

We first declare the function and then at the end of the program we definethe function.
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POINTERS:- The memory of your computer can be imagined as a

succession of memory cells, each one of the minimal sizethat computers manage (one byte). These single-bytememory cells are numbered in a consecutive way, so as,

within any block of memory, every cell has the samenumber as the previous one plus one.

This way, each cell can be easily located in the memorybecause it has a unique address and all the memory cellsfollow a successive pattern. For example, if we are looking

for cell 1776 we know that it is going to be right betweencells 1775 and 1777, exactly one thousand cells after 776and exactly one thousand cells before cell 2776.

The general form of declaring the pointer istype*ptr;


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REFERENCES:-

It is an alternative name for an object. Areference variable provides an alias for apreviously defined variable. Its declaration

consists of a base type, an &(ampersand), areference variable name equated to avariable name.

the general form of declaring is:-type&ref-var = var-name;


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CONSTANTS:-

C++ constants are not very different from any C++ variable. Theyare defined in a similar way and have the same data types and thesame memory limitations. However, there is one major difference -once a constant has been created and value assigned to it then that

value may not be changed. Defining Constants with C++

There are actually three ways of defining a constant in a C++ program:A. by using the preprocessorB. by using the constkey wordC. by using enumerators - these will have a range of integer valuesIt's also worth noting that there are two types of constant: literal and

symbolic.the general form of declaring a variable is:-

const int upperage = 50;


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USER DEFINED DERIVED DATA TYPES

CLASS

STRUCTURE

UNION

ENUMERATION


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Class: A class is a collection of variables and

function under one reference name. it is the

way of separating and storing similar data

together. Member functions are often the

means of accessing, modifying and operating

the data members (i.e. variables). It is one

of the most important features of C++ since

OOP is usually implemented through the use

of classes.


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Classes are generally declared using thekeyword class, with the followingformat:

class class_name { access_specifier_1:member1;

access_specifier_2:

member2; ...} object_names;


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STRUCTURES:- A data structure is a group of data elements grouped together under one name. These

data elements, known as members, can have different types and different lengths.

Data structures are declared in C++ using the following syntax:

struct structure_name {member_type1 member_name1;member_type2 member_name2;member_type3 member_name3;..} object_names;

where structure_name is a name for the structure type, object_name can be a set ofvalid identifiers for objects that have the type of this structure. Within braces { }there is a list with the data members, each one is specified with a type and a valididentifier as its name.

Structure is different from an array in the sense that an array represents an aggregateof elements of same type whereas a structure represents an aggregate of elements ofarbitrary types..


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Unions allow one same portion of memory to be accessed as different data types, sinceall of them are in fact the same location in memory. Its declaration and use is similar tothe one of structures but its functionality is totally different:

union union_name {

member_type1 member_name1;



.

.

} object_names;

All the elements of the union declaration occupy the same physical space in memory. Itssize is the one of the greatest element of the declaration.

all of them are referring to the same location in memory, the modification of one of theelements will affect the value of all of them. We cannot store different values in them

independent of each other.One of the uses a union may have is to unite an elementary type with an array orstructures of smaller elements.

The exact alignment and order of the members of a union in memory is platformdependant. Therefore be aware of possible portability issues with this type of use.


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ENUMERATION:-

It can be used to assign names to integer constants.//Program to illustrate Enumerator

#include

void main(void)

{

enum type{POOR,GOOD,EXCELLENT};//this is the syntax of enumerator

int var;

var=POOR;//this makes programs more understandable

cout


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We have so many data types to allow theprogrammer to take advantage of hardwarecharacteristics. Machines are significantlydifferent in their memory requirements,memory access times, and computation speeds.


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