Passing an array with integer values and char indexes to a function in Pascal

In traditional Pascal, before you can pass something like your array to a function, you have to declare a type that your array is an instance of, like this

type
  TSimpleArray = Array['A'..'Z', '0'..'9'] of integer;
var
  ASimpleArray : TSimpleArray;

In other words, you can't specify the array's bounds in the definition of the function/procedure.

Once you've defined your array type like the above, you can declare a function (or procedure) that has a parameter of the defined type, like this:

function ArrayFunction(SimpleArray : TSimpleArray) : Integer;
var
  C1,
  C2 : Char;
begin
  ArrayFunction := 0;
  for C1 := 'A' to 'Z' do
    for C2 := '0' to '9' do
      ArrayFunction := ArrayFunction + SimpleArray[C1, C2];
end;

which obviously totals the contents of the array.

More modern Pascals like Delphi and FPC's ObjectPascals also support other ways of declaring an array-type parameter, but they have to be zero-based (which precludes the use of char indexes). Delphi and FPC also support the use of `Result' as an alias for the function name, as in

function ArrayFunction(SimpleArray : TSimpleArray) : Integer;
[...]
begin
  Result := 0;

which saves time and effort if you rename a function or copy/paste it to define another function.