In Computer Sciences, an array type is a data type used for keeping a collection of elements of a certain data type together.
Programming languages often support this data type as part of their syntax.
There can be, for example, an array of integer numbers declared & defined as follows:
- int is type of elements inside array,
- num is array's name,
- SIZE is a constant, that is used in determining array's size.
Access to each of variables that is part of an array is done via the index variable or a constant, for example as follows:
num; // this is expression that gives value of a num array's variable at position 3.
num[i]; // this is expression that gives value of a num array's variable at position
// determined by value of 'i' variable.
num = a; // this is assignment instruction that assigns value of a variable 'a' to a num
// array at position 3.
There can be multidimensional arrays, or arrays of arrays, for example:
int num2[SIZ_DIM_1][SIZ_DIM_2]; // 2-dimensional array declaration & definition,
// without initialization perhaps.
a = num2; // expression evaluation & assignment to 'a' variable.
num2 = a; // assignment to array variable at position (1,2).
int num3[SIZ_DIM_1][SIZ_DIM_2][SIZ_DIM_3]; // 3-dimensional array declaration
// & definition, without initialization perhaps.
Access time to any of array's variables can be measured by a constant, or should be such, regardless of array's size.
See also: Basic Data Structures.