Suppose you wanted to read in 5000 integers and do something with them. How would you store the integers?

You could use 5000 variables, lapsing into:

But this would grow tedious (after declaring those variables, you have to read values into each of those variables).

An array contains several storage spaces, all the same type. You refer to each storage space with the array name and with a subscript. The type definition is:

The data type can be anything, even another array. Any enumerated type will do. You can specify the enumerated type inside the brackets, or use a predefined enumerated type. In other words,

is equivalent to

Aside: This is how strings are actually managed internally &mdash as arrays. Back before modern Pascal compilers added native support for strings, programmer had to handle it themselves, by declaring:

   type
      String = packed array [0..255] of char;

and using some kind of terminating character to signify the end of the string. Most of the time it's the null-character (ordinal number 0, or ord(0)). The packed specifier means that the array will be squeezed to take up the smallest amount of memory. Arrays of characters representing strings are often referred to as buffers, and errors in handling them in the C or C++ programming languages have led to the buffer overruns which resulted in the Slammer worm and other security holes. A buffer overrun occurs when you try to put, say, a 200-character string into a 150-length array. What happens to the 50 characters at the end? Does it overwrite other parts of memory, or does the program realize that the array can't hold that many and crash? A crash is considered preferable to a buffer overrun because the program shuts down but does not allow an attacker to gain control of an unauthorized area of your system. Try it in Pascal and see what happens.

Arrays are useful if you want to store large quantities of data for later use in the program. They work especially well with for loops, because the index can be used as the subscript. To read in 50 numbers, assuming the following definitions:

type
    arraytype = array[1..50] of integer;
var
    myarray : arraytype;

use:

   for count := 1 to 50 do
      read (myarray[count]);

Brackets [ ] enclose the subscript when referring to arrays.