Creating an Array: Difference between revisions

As with all ALGOL 68 declarations the programmer has the choice of using the full declaration syntax, or using [[syntactic sugar]] - c.f. "sugared" variables below.

<lang algol>

REF []INT numbers = HEAP [1:10] INT;

HEAP [1:10]INT sugared hnumbers; # from global memory #

LOC [1:10]INT sugared lnumbers1; # from the stack #

[10]INT sugared lnumbers2; # from the stack - LOC scope is implied #

</lang>

<lang algol>

[]STRING cwords = ( "these", "are", "arrays" ); # array is a constant and read-only (=) #

[3]STRING vwords := ( "these", "are", "arrays" ); # array is a variable and modifiable (:=) #

</lang>

You can also declare the size of the array and initialize the values at the same time:

<lang algol>

REF []INT more numbers = LOC [3]INT := ( 21, 14 ,63 );

[]INT sugared more cnumbers = ( 21, 14 ,63 );

[3]INT sugared more vnumbers := ( 21, 14 ,63 );

</lang>

For Multi-Dimensional arrays you declare them the same except for a comma in the type declaration.

<lang algol>

REF [][]INT number matrix = LOC [3][2] INT;

[3,2]INT sugared number matrix1; # an matrix of integers #

[3][2]INT sugared number matrix2; # an array of arrays of integers #

</lang>

As with the previous examples you can also initialize the values of the array, the only

<lang algol>

[][]STRING string matrix = ( ("I","swam"), ("in","the"), ("freezing","water") );

</lang>

<lang algol>

REF [][] STRING funny matrix = LOC [2][2]STRING := ( ("clowns", "are") , ("not", "funny") );

[2][2] STRING sugared funny matrix := ( ("clowns", "are") , ("not", "funny") );

</lang>

<lang algol>

[-10:10] INT balanced; # for example -10 #

</lang>

<lang algol>

FLEX [-10:10] INT flex balanced;

</lang>

<lang algol>

[-10:10] REF INT array of pointers to ints;

OD

</lang>

<lang algol>

MODE VEC = FLEX[0]REAL; # VECTOR is builtin in ALGOL 68R #

MODE BOOLS = FLEX[0]BOOL; # BITS is builtin in the standard #

</lang>

<lang algol>

VEC x := (1, 4, 5);

SKIP

</lang>