Access to the single elements of an array

Each single element of an array object can be accessed as if it were a separate variable.

Access to the single elements of an array

Syntax:

arrayName[index]

where

• arrayName is the name of the array variable that contains a reference to the array we want to access
• index is an expression of type int with non-negative value that specifies the index of the element we want to access.

Semantics:

Accesses the element of the array arrayName in the position specified by index to read or modify it.

If the array arrayName contains N elements, the evaluation of the expression index must return an integer in the interval [0, N - 1]; if this is not the case, a runtime error occurs when the program is run.

Example:

int[] a;        // a is a variable of type array of integers
a = new int[5]; // creation of an array object with 5 elements of type int;
                // the array object is referenced by the array variable a
a[0] = 23;      // assignment to the first element of the array
a[4] = 92;      // assignment to the last element of the array
a[5] = 16;      // ERROR!  the index 5 is not in the range [0,4]

Note: It is very important to remember that, when an array contains N elements (N = 5 in the example), the indexes used to access the elements must necessarily be integers in the interval [0, N - 1]. Otherwise, a runtime error occurs when the program is executed. In the example, an error is signaled when the statement a[5]=16;.