2. WHAT IS ARRAY?
• An array is a group of consective memory
locations with same name and data type.
• Simple variable is a single memory location with
unique name and a type. But an Array is
collection of different adjacent memory
locations. All these memory locations have one
collective name and type.
• The memory locations in the array are known as
elements of array. The total number of elements
in the array is called length.
• The elements of array is accessed with
reference to its position in array, that is call
index or subscript.
3. DECLARATION OF AN ARRAY:
Like a regular variable, an array must be declared
before it is used. A typical declaration for an array in
Visual C++ is:
type name [elements];
type is a valid type (like int, float...)
name is a valid identifier
elements field (which is always enclosed in square
brackets []), specifies how many of these elements
the array has to contain.
5. ADVANTAGES OF ARRAY:
Arrays can store a large number of value
with single name.
Arrays are used to process many value
easily and quickly.
The values stored in an array can be
sorted easily.
The search process can be applied on
arrays easily.
8. ONE DIMENSIONAL ARRAY:
A one dimensional array is one in which one
subscript /indices specification is needed to
specify a particular element of array
Declaration :
Data_type array_name [size of array ];
Eg:
Int num[10];
10. MEMORY REPRESENTATION:
num[0] num[1] num[2] num[3] num[4] num[5] num[6] num[7] num[8] num[9]
2000 2002 2004 2006 2008 2010 2012 2014 2016 2018
starting Address of location
Total memory in bytes that an array is occupied :
Size of array=size of array*size of(base type)
Hear,
10*2=20
39 56 23 98 6 56 9 2 54 67
11. TWO DIMENSIONAL ARRAY:
A 2-d array is an array in which each element is
itself an array
i.e int num[4][3]
0 1 2
0
1
2
3
No of
rows
No
of
colu
mns
No of element in
2-D array =M*N
Num [2][1]
13. MEMORY REPRESENTATION:
Total bytes= no of rows*no of columns*size of(base type)
Memory reprsentation in 2-D array:
char A [2][3]
A[0][0] A[0][1] A[0][2] A[1][0] A[1][1] A[1][2]
5001 5002 5003 5004 5005 5006
14. MULTI DIMENSIONAL ARRAY:
An array with dimensions more than
two .The maximum limit of array is compiler
dependent
Declaration:
Data_type name [a][b][c][d][e][f]…….[n];
Array of 3 or more dimensional are not often
use because of huge memory requirement
and complexity involved
16. ARRAY INITIALIZATION:
C++ provides the facility of array initialization at the time of
declaration .General form of array initialization is as:
Type array_name[size 1]…..[size N] ={vale list};
Eg:
Int days_month[12]={31,25,29,03,31,19,20,31,18,20,31,29};
Char string[6]={‘a’,’r’,’g’,’y’,’d’,’0’};
2-D array are also initialized in same way as linear array
Int cube[4][2]={ 1,3,
4,6,
9,37,
5,78
};
17. UNSIZED ARRAY INITIALIZATION:
C++ allowed you to skip the size of array in an array initialization
statement C++ automatically create an array big enough to hold all
the initializers present
Char S1[] =“ first string ”;
you skip the size, you must give list of initializers so that C++ can
calculate the size of array
Int val []={3,5,6,2,8,9,6,4};
Int cube [] [2] ={ 1,3,
67,7,
6,87,
};
18. STRING AS ARRAY:
C++ does not have a String data type ,it
impairments string as 1-D character Arrray .A
string as a character array is terminate by a
null character ‘0’
Char str 1 [11];
Char square [][]={ ‘first string’,
‘second string’,
‘third string’
};
19. SORTING ARRAYS:
Sorting is a process of arranging
the value of array in a particular
order. An array can be sorted in
two order.
o Ascending Order
o Descending Order
21. String
C++ strings are sequences of characters stored in a char
array.
Strings are used to store words and text.
String index starts with o last character of string in
null(0)
Strings in C++ can be defined either using
the std::string class or the C-style character arrays.
22. C Style Strings
These strings are stored as the plain old array of
characters terminated by a null character ‘0’. They
are the type of strings that C++ inherited from C
language.
Syntax:
Char str[]=“greeksforgreeks”
23. // C++ Program to demonstrate strings
#include <iostream>
using namespace std;
int main()
{
char s[] = "GeeksforGeeks";
cout << s << endl;
return 0;
}
Output:GreeksforGreeks
24. std::string Class
These are the new types of strings that are introduced
in C++ as std::string class defined inside <string> header
file. This provides many advantages over conventional
C-style strings such as dynamic size, member functions,
etc.
Syntax:std::string str("GeeksforGeeks");
25. String manipulator functions
C++ supports a wide range of functions that
manipulate null-terminated strings. These are:
strcpy(str1, str2): Copies string str2 into string
str1.
strcat(str1, str2): Concatenates string str2 onto
the end of string str1.
strlen(str1): Returns the length of string str1.
strcmp(str1, str2): Returns 0 if str1 and str2 are
the same; less than 0 if str1<str2; greater than 0 if
str1>str2.
strchr(str1, ch): Returns a pointer to the first
occurrence of character ch in string str1.
strstr(str1, str2): Returns a pointer to the first
occurrence of string str2 in string str1.
26. Pointer
Pointer is a variable that holds the memory address of
another variable.
Declaration of array is
datataype *pointer-variable;
Pointer variable is the name of the pointer, datatype
refers to valid c++ datatypes.
27. Int *ptr,a; //declaration
Ptr=&a; //initialization
Ptr contains address of variabler a,& is addess operator
or reference operator to retrieve the address of the
variable.
Example int a=10;
int *ptr=&a;
28. Pointer arithmetic
Pointer arithmetic means performing arithmetic
operations on pointers. It refers to the operations that
are valid to perform on pointers. Following are the
arithmetic operations valid on pointers in C++:
Incrementing and Decrementing Pointers
Addition of Constant to Pointers
Subtraction of Constant from Pointers
Subtraction of Two Pointers of the Same Type
Comparison of Pointers
29. Incrementing and Decrementing Pointer in C++
Incrementing or decrementing a pointer will make it
refer to the address of the next or previous data in the
memory. This process differs from incrementing and
decrementing numeric data.
30. Incrementing a Pointer
Incrementing a pointer will depend on the type of
variable address stored in the pointer. If the pointer
stored the address of the integer type variable then the
size of the integer pointer can be 4 bytes.
For example, If a pointer holds the address 1000 and
we increment the pointer, then the pointer will be
incremented by 4 or 8 bytes (size of the integer), and
the pointer will now hold the address 1004.
31. Decrementing a Pointer
When we apply a decrement operation on the pointer
then the pointer is decremented by 4 or 8 bytes
depending upon the machine.
For example, If a pointer holds the address 1004 and
we decrement the pointer, then the pointer will be
decremented by 4 or 8 bytes (size of the integer), and
the pointer will now hold the address 1000.
33. Addition of Constant to Pointers
We can add integer values to Pointers and the pointer is
adjusted based on the size of the data type it points to.
For example, if an integer pointer stores the address
1000 and we add the value 5 to the pointer, it will store
the new address as:
35. Subtraction of Constant from Pointers
We can also subtract a constant from Pointers and it is
the same as the addition of a constant to a pointer. For
example, if an integer pointer stores the address 1000
and we subtract the value 5 from the pointer, it will
store the new address as:
1000 - (5 * 4(size of an integer)) = 980
36. Subtraction of Two Pointers of the Same Datatype
The Subtraction of two pointers can be done only when
both pointers are of the same data type. The
subtraction of two pointers gives the number of
elements present between the two pointers
37. Comparison of Pointers
In C++, we can perform a comparison between the two
pointers using the relational operators(>, <, >=, <=, ==,
!=). We generally use this operation to check whether
the two-pointer as pointing to the same memory
location or not.
![DECLARATION OF AN ARRAY:
Like a regular variable, an array must be declared
before it is used. A typical declaration for an array in
Visual C++ is:
type name [elements];
type is a valid type (like int, float...)
name is a valid identifier
elements field (which is always enclosed in square
brackets []), specifies how many of these elements
the array has to contain.](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-3-320.jpg)
![EXPLANATION:
INT NUM[6]
size of
the
array
Base name of
type array](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-4-320.jpg)
![ONE DIMENSIONAL ARRAY:
A one dimensional array is one in which one
subscript /indices specification is needed to
specify a particular element of array
Declaration :
Data_type array_name [size of array ];
Eg:
Int num[10];](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-8-320.jpg)
![MEMORY REPRESENTATION:
num[0] num[1] num[2] num[3] num[4] num[5] num[6] num[7] num[8] num[9]
2000 2002 2004 2006 2008 2010 2012 2014 2016 2018
starting Address of location
Total memory in bytes that an array is occupied :
Size of array=size of array*size of(base type)
Hear,
10*2=20
39 56 23 98 6 56 9 2 54 67](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-10-320.jpg)
![TWO DIMENSIONAL ARRAY:
A 2-d array is an array in which each element is
itself an array
i.e int num[4][3]
0 1 2
0
1
2
3
No of
rows
No
of
colu
mns
No of element in
2-D array =M*N
Num [2][1]](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-11-320.jpg)
![MEMORY REPRESENTATION:
Total bytes= no of rows*no of columns*size of(base type)
Memory reprsentation in 2-D array:
char A [2][3]
A[0][0] A[0][1] A[0][2] A[1][0] A[1][1] A[1][2]
5001 5002 5003 5004 5005 5006](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-13-320.jpg)
![MULTI DIMENSIONAL ARRAY:
An array with dimensions more than
two .The maximum limit of array is compiler
dependent
Declaration:
Data_type name [a][b][c][d][e][f]…….[n];
Array of 3 or more dimensional are not often
use because of huge memory requirement
and complexity involved](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-14-320.jpg)
![ARRAY INITIALIZATION:
C++ provides the facility of array initialization at the time of
declaration .General form of array initialization is as:
Type array_name[size 1]…..[size N] ={vale list};
Eg:
Int days_month[12]={31,25,29,03,31,19,20,31,18,20,31,29};
Char string[6]={‘a’,’r’,’g’,’y’,’d’,’0’};
2-D array are also initialized in same way as linear array
Int cube[4][2]={ 1,3,
4,6,
9,37,
5,78
};](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-16-320.jpg)
![UNSIZED ARRAY INITIALIZATION:
C++ allowed you to skip the size of array in an array initialization
statement C++ automatically create an array big enough to hold all
the initializers present
Char S1[] =“ first string ”;
you skip the size, you must give list of initializers so that C++ can
calculate the size of array
Int val []={3,5,6,2,8,9,6,4};
Int cube [] [2] ={ 1,3,
67,7,
6,87,
};](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-17-320.jpg)
![STRING AS ARRAY:
C++ does not have a String data type ,it
impairments string as 1-D character Arrray .A
string as a character array is terminate by a
null character ‘0’
Char str 1 [11];
Char square [][]={ ‘first string’,
‘second string’,
‘third string’
};](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-18-320.jpg)
![C Style Strings
These strings are stored as the plain old array of
characters terminated by a null character ‘0’. They
are the type of strings that C++ inherited from C
language.
Syntax:
Char str[]=“greeksforgreeks”](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-22-320.jpg)
![ // C++ Program to demonstrate strings
#include <iostream>
using namespace std;
int main()
{
char s[] = "GeeksforGeeks";
cout << s << endl;
return 0;
}
Output:GreeksforGreeks](https://image.slidesharecdn.com/arrayandpointerstring-250304131640-820ab233/85/arraytypes-of-array-and-pointer-string-in-c-pptx-23-320.jpg)
