ONE-DIMENSIONAL ARRAY

Array is used to store many pieces of data of the same type 

One-dimensional array structure
 

Declare a one-dimensional array

Data type  [] arrayname;
or
Data type arrayname [];

Example

int [] testScore;
or
int testScore[];

Create a one-dimensional array
Allocate the memory for the array. Define the number of array elements

arrayname [ ] = new datatype [arraysize];
arraysize: an integer value or an  integer variable

Assume that you have declared the array.
Example:  Create a one-dimensional array of 100 elements. 

int [] testScore;  

testScore = new int[100];

Declare and initialize a one-dimensional array
int [] A = {10,60.20,5,90};
or
int A [] = {10,60,20,5,90};

Arrayname.length è Return array size

 Example
Declare and initialize a one-dimensional array
Accumulate all the array elements
Display the accumulated value 

int [] A = {10, 60, 40, 30, 80}; 

1^st Solution

sum= A [0] +A[1] + A[2] + A[3] + A[4];

 2^nd Solution  Use a for loop 

sum= 0  

for( int i =0 ; i< A.length; i = i + 1 )
    sum = sum + A[i];
System.out.println( sum);

Example

Input 5 array elements of type integer form the user

Strings;

in [] A= new int [5];
for( int i=0; i < A.length; i = i +1)
   {s= JOptionPane.showInputDialog” Enter a Number”);
     A[i]= Integer.ParseInt(s);
    }

                        0                      1                      2                      3                      4

A 

Find the index of the largest array element

 int largestelement = A[0];
int largest index =0;
for( int i=1; i<A.length; i++)
{    if(A[i]> largestelement)
        {largestelement =A[i];
          largestindex = i;
        }
}

Analyze the coding

largestElement = A[0]
largestindex =0

i = 1

A[1] >largestElement à 40>30
     largest Element à A[1] = 40
     largest index= 1

i = 2

A[2] >largestElement à 60>40
     largest Element à A[2] = 60
     largest index= 2