Arrays

• An array is a group of contiguous memory locations that all have the same name and the same type.
• To refer to a particular memory location, we specify:
  • the array name
  • its position number, also known as its subscript.
• For example, below we have an array whose name is c, containing 6 elements.
• The element's subscript is enclosed in brackets ([ ]).
• The first element is c[0]; the 6th, and last, in this case, is c[5].

Array name & subscript	value
c[0]	-45
c[1]	6
c[2]	72
c[3]	1543
c[4]	-89
c[5]	0

• Array names have the same rules as other identifier names: They can be made of letters, numbers, the underscore (_), and the dollar sign ($), but cannot begin with a number.
• The subscript must be an int expression.

  Here are some valid element references (let int i = 2): c[2], c[i], c[i - 2], c[2*i - 1].

  What elements do they refer to?

• If we start with the array above, and i = 2, what do the following statements do (assume the array c holds int's and that x is an int)?

  c[2*i - 1] = 7 + c[i-1] + 3*c[i]++;

  x = c[2*i -1] / 2;

• The number of elements in the c array is given by the expression c.length.

  You can imagine how handy this can be when specifying loop limits, for example.

  for (int i = 0; i < c.length; i++)

c[i] = 0;

• Brackets, [ ], are an operator, and have the highest precedence: the same as parentheses, ( ).