Arrays introduction. 1-D arrays 2-D arrays Multi-Dimensional arrays

1. Arrays

2. Prepared by:
Kashif Nawab
St. of IT
UOG Narowal

3. What is Array?
An array is a group of consecutive memory locations
with same name and type. Simple variable is a single
memory location with unique name and type. But an
array is a collection of different adjacent memory
locations.
 These memory locations in the array are called
elements of array.
 The total number of elements in the array is called its
length.

4. Advantages of array:
o Arrays can store a large number of values with
single name.
o Arrays are used to process many values
quickly and easily.
o The values stored in an array can be sorted
easily.
o A search process can be applied on arrays
easily.

5. Declaring One dimensional
Array:
The syntax of declaring one-dimensional array is:
Data_type Identifier[length];
Data_type Indicates data type of values.
Identifier Indicates the name of array.
Length Indicates total number of elements in
array.

6. For Example:
int marks[5];
Index of each element 0 1 2 3 4
Name of array marks

7. Array initialization
The syntax of array initialization is :
Data_type Identifier[length]={list of values};
List of values It indicates the values to initialize the array. These
values must b constant.

8. Example:
int marks[5]={70,75,90,60,85};
Index of each element 0 1 2 3 4
Name of array marks 70 75 90 60 85

9. Accessing individual elements in an
array:
The syntax for accessing element is as follows :
Array_Name[index];
Array_Name Indicates the name of array.
Index Indicates the index element
to be accessed.

10. Example:
int marks[5];
int marks[0]=70;
int marks[1]=75;
int marks[2]=90;
int marks[3]=60;
int marks[4]=85;

11. A simple program:
Write a program that inputs five integers
from user and stores them in an array. It
then displays all values in array without
using loop.

12. #include<iostream>
Int main( )
{
int array[3];
cout<<“enter five integers: “<<endl;
cin>>array[0];
cin>>array[1];
cin>>array[2];

13. cin>>array[3];
cin>>array[5];
Cout<<“the values in array are : “<<endl;
cout<<array[0]<<endl;
cout<<array[1]<<endl;
cout<<array[2]<<endl;
cout<<array[3]<<endl;
cout<<array[4]<<endl;

14. return 0;
}

15. Write a program that inputs five integers
from user and stores them in an array. It
then displays all values in array using
loop.

16. #include<iostream>
Int main( )
{
int arr[5],i;
for(i=0 ; i<5 ; i++)
{
cout<<“Enter an integer : “;
cin>>arr[i];
}

17. cout<<“The values in array are : n
for(i=0 ; i<5 ; i++)
cout<<arr[i]<<endl;
return 0;
}

18. Output:
Enter an integer : 32
Enter an integer : 46
Enter an integer : 50
Enter an integer : 75
Enter an integer : 84
The values in array are :
32
46
50
75
84

19. Write a program that input five number
from user in array and display maximum
number.

20. #include<iostream>
using namespace std;
main()
{
int a[5],i,max;
for(i=0;i<5;i++)
{
cout<<"Enter number : ";
cin>>a[i];
}
max=a[0];
for(i=0;i<5;i++)
if(max<a[i])
max=a[i];
cout<<"Maximum Number is : "<<a[i];
return 0;
}

21. Output:
Enter number : 8
Enter number : 13
Enter number : 5
Enter number : 15
Enter number : 14
Maximum Number is 15

22. Two-Dimensional Arrays
Two-dimensional array can be considered as a table that
consists of rows and column. Each element in 2-D array is
referred with the help of two indexes. One index is used to
indicate the row and the second index indicates the column of
the element.

23. Syntax:
Data_type identifier[Rows][Cols];
For Example:
The following statement declares a 2-D array with four rows and three
columns.
Int Arr[4][3];

24. A 2-D array and its indexes

25. Accessing elements of 2-D array
The array name and indexes of row and column are used to access
individual element of a 2-D array. For example, the following statement will
store 20 in the second column of first row.
Int Arr[0][1]=100;
OR
By assigning variables to indexes:
R=0;
C=1;
Arr[R][C]=100;

26. Entering Data in 2-D array
You can enter data in any element of array using array name and index of
element. For example:

27.  Nested loops are frequently used to enter data in 2-D arrays.
 The outer loop are used to refer to the rows in array.
 Inner loop are used to refer to the columns in array.

28. Write a program that stores integer values
in an array of 2 rows and 4 columns.

29. #include<iostream>
using namespace std;
main()
{
int Array[2][4],i,j;
for(i=0;i<2;i++)
for(j=0;j<4;j++)
{
cout<<"enter values : ";
cin>>Array[i][ j];
}
cout<<"The values in array aren";
for(i=0;i<2;i++)
{
for(j=0;j<4;j++)
cout<<Array[i][ j]<<"t";
cout<<endl;
}
return 0; }

30. Output:

31. Initialization 2-D Arrays
The process of initialization is performed by assigning the initial values in
braces separated by commas at the time of declaration.
For example:
Int array[3][4]={ {12,5,22,84},
{95,3,41,59},
{77,6,53,62} };
OR
Int array[3][4]={ {12,5,22,84}, {95,3,41,59}, {77,6,53,62} };

32. Initialization can also be performed without using inner braces.
Int array[3][4]={ 12,5,22,84,
95,3,41,59,
77,6,53,62 }
OR
Int array[3][4]= { 12,5,22,84,95,3,41,59,77,6,53,62 }

33. Write a program that initializes a 2-D
array of 2 rows and 3 columns and then
display its values.

34. #include<iostream>
using namespace std;
main()
{
int i,j,a[2][3]={0,1,2,3,4,5};
for(i=0;i<2;i++)
{
for(j=0;j<3;j++)
cout<<"arr["<<i<<"]["<<j<<"] "<<a[i][ j]<<"t";
cout<<"n";
}
return 0;
}

35. Output:

36. Write a program that initializes a two-dimensional
array of 2 rows and 4 columns and then displays the
maximum and minimum number in the array.

37. #include<iostream>
using namespace std;
main()
{
int max,min,i,j;
int A[2][4]={15,21,9,84,33,72,18,47};
max=min=A[0][0];
for(i=0;i<2;i++)
for(j=0;j<4;j++)

38. Program continues
if(A[i][j]>max)
max=A[i][j];
if(A[i][j]<min)
min=A[i][j];
}
cout<<"Maximum number is : "<<max<<endl;
cout<<"Minimum Number is : "<<min<<endl;
return 0;
}

39. Output:
Maximum Number is 84
Minimum Number is 9