Arrays

You may declare arrays of any data type, including classes. The general form of a singly dimensioned array is

type var-name[size];

where type specifies the data type of each element in the array and size specifies the number of elements in the array. For example, to declare an integer array x of 100 elements, you would write

int x[100];

This will create an array that is 100 elements long with the first element being 0 and the last being 99. For example, the following loop will load the numbers 0 through 99 into array x:

for(t=0; t<100; t++) x[t] = t;

Multidimensional arrays are declared by placing the additional dimensions inside additional brackets. For example, to declare a 10 × 20 integer array, you would write

int x[10][20];

Arrays can be initialized by using a bracketed list of initializers. For example,

int count[5] = { 1, 2, 3, 4, 5 }; 

In C89 and C++, array dimensions must be specified by constant values. Thus, in C89 and C++, all array dimensions are fixed at compile time and cannot change over the lifetime of a program. However, in C99, the dimensions of a local array can be specified by any valid integer expression, including those whose values are known only at compile time. This is called a variable- length array. Thus, the dimensions of a variable-length array can differ each time its declaration statement is encountered.