arrayy.ppt

Arrays
Declaration & Initialization

For understanding the arrays properly, let us consider
the following program:
main( )
{
int x ;
x = 5 ;
x = 10 ;
cout<< x<<endl ;
}

• There are situations in which we would want to store
more than one value at a time in a single variable.
• For example, suppose we wish to arrange the marks
obtained by 100 students
• In such a case we have two options to store these marks

• Construct 100 variables to store marks obtained by 100
different students, i.e. each variable containing one
student’s marks.
• Construct one variable capable of storing or holding all
the hundred values.

• Obviously, the second alternative is better.
• A simple reason for this is, it would be much easier to
handle one variable than handling 100 different variables

Arrays
• When we want to store more than one value at a time
in a single variable, we require an array
• Array is the collection of similar data types stored in
contiguous memory location
• Each data item of an array is called an element.
• Each element is located in separated memory location.

• Each of elements of an array have different index no.
known as subscript
• Thus, an array can be considered as a subscripted
variable
ADVANTAGE:
• Array variable can store more than one value at a time
where other variable can store one value at a time.

An array of integers
• All elements in the array are of type integer
• The length of the array is 10
• The array is indexed from 0 to 9
3 16 -1 0 8 7 1 55 -3 1

• The element at index 0 is 3
3 16 -1 0 8 7 1 55 -3 1
index
0

3 16 -1 0 8 7 1 55 -3 1
index
4

3 16 -1 0 8 7 1 55 -3 1
index
7

3 16 -1 0 8 7 1 55 -3 1
index
9

An array of Floats and Characters
• Array of Floats
• Array of Characters
3.5 1.4 7.8 8.8 9.4 9.9 3.5 6.8 5.0 5.5
W E L L C O M E B K

NOT AN ARRAY
3 1.5 -1 0 6.7 R D 5.5 -3 1

Array Declaration
• The statement int A;
declares a single integer variable named A
Syntax: type arrayName [ arraySize ];
• The statement int A[5];
float B[10];
declares
• Array variable A that can hold 5 integer values
• Array variable B that can hold 10 float values
• The size and type of arrays cannot be changed after its
declaration.

Initializing Array
• Syntax:
type arrayName [ arraySize ]={element1,element2….elementN };
• It's possible to initialize an array during declaration.
int A[5] = {35, 20, 40, 57, 19};
• Another method to initialize array during declaration:
int A[] = {35, 20, 40, 57, 19};
OR
A[0]= 35 ;
A[1]= 20 ;
A[2]= 40 ;
A[3]= 57 ;
A[4]= 19 ;

C++ program
• # include<iostream.h>
• #include<conio.h>
• main()
• {
• int x[5] , i;
• cout<<“Enter values into array”<<endl;
• for(i=0;i<5l;i++)
{
• cin>>x[i];
}
• cout<<“The values you entered into array are ”<<endl;
for(i=0;i<5l;i++)
• {
• cout<<x[i]<<endl;
• }
• }

TWO – DIMENTIONAL ARRAY:
If you want to store data into table or matrix form at that time you
can use the two dimensional array.
Declaration of two dimentional array:
Syntax : data_type array-name[dim1][dim2];
Where dim1 indicates total rows and dim2 indicates total
columns.
Ex: ITEM 1 ITEM2ITEM 3
SALES MAN 1 310 275 365
SALES MAN 2 210 190 325
SALES MAN 3 405 235 240
SALES MAN 4 260 300 380

Initializing two dimentional array:
Ex: int table[2][3] = {0,0,0,1,1,1};
int table[2][3] = {
{0,0,0},
{1,1,1}
} ;

Initializing two dimentional array:
When the array is completely initialized with all values,
we need not specify the size of the first dimension. That
is, the statement is permitted.
int table[][3] = {
{0,0,0} ,
{1,1,1)
};

C++ program
• # include<iostream.h>
• #include<conio.h>
• main()
• {
• int x[2][3] , i,j;
• cout<<“Enter values into array”<<endl;
• for(i=0;i<2l;i++)
• {
• for(j=0;j<3;j++)
{
• cin>>x[i][j];
}
}

• cout<<“The values you entered into array are ”<<endl;
• for(i=0;i<2l;i++)
• {
• for(j=0;j<3;j++)
{
• cout<<x[i][j];
}
}
}

arrayy.ppt

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