Consideraciones acerca de la alternativa como resultado científico

Array subscripts begin with 1. _{Array variables can} be _{dimensioned only once}

in a _program. Example:

10 DIM SALES(10,1O),SAf.EM$(10)*30,TEMP$*lO

When _{executed, the following allocations are} made:

SALES : two-dimensional numeric array of size 10 by 10

SALEM$: _{one-dimensional character}

array of size 10 by

I;

each _character element _{with length} 30 TE!'ÍP$ : single character variable with length 10

END

The END

statement

_is

used _{to terminate a DeltaBASIC program.}

_It

_closes

_all

files

and _returns DeltaBASIC _{to the} command/program

_edit

rnode. Program

_exit

_should be _{through the} END

statement

_if

you want _{to remain}

_in

DeltaBASIC command/program _edit mode _{afterwards. Terminating a program with}

END _{(or OFF)}

is

especially important to ensure that

files

otherwise

_left

open

are properly closed.

Example: 9999 END

When _{program termination}

_is

_{required, statement} 9999

_is

_executed.

_All

_open

files

are closed and DeltaBASIC enters the command/program

edit

mode.

EXIT {IOERR _line-mm} {,IOERR line—mm)

_(9···)

{DUPKEY _line-num) {,DUPKEY _line-num}

{NOKEY _line-mm) {,NOKEY line-mm)

{EOF _{line-mm) {,E0F line-num)}

The EXIT _{statement can} be used _with OPEN, READ, WRITE, REWRITE, and CLOSE

statements to provide branching when the specified errors occur. (See the appropriate statements for more information concerning these

errors.)

The EXIT _statement can be accessed only by way of one of these I/O statements; when _otherwise encountered during execution, EXIT

_is

_ignored much _{as a} REM

statement would be.

EXIT

_is

_{especially useful} when _{a number of I/O operations} have _the saíne _error

processing

_lines.

Each _{I/O statement} would _{contain an} EXIT

_line

number

referring

to the EXIT _{statement, which} would _{in turn contain the}

_line

numbers

for the various _error traps.

Examples:

10 READ _#1,USING

II:

A,B EOF _{100 IOERR 130}

II

FORM

...

0 0 0

lOó REM _END-OF-FILE ERROR _PROCESSING

105

...

0 0 O

130 REM _I/O ERROR _PROCESSING

135

...

EXIT

_is

_not used _in

_this

_program segment.

_If

an

end-of-file

_{error occurs}

while

_file

#1

_is

_{being read, the program} branches _to

_line

100

_for

_recovery

processing.

_If

an I/O error occurs, the program branches to

line

130. Yow _{consider an equivalent} method _{using the} EXIT _statement.

10 READ _#I,USING

II:

A,B EXIT 20

11 FORM

...

20 EXIT EOF 1OO,IOERR 130

0 9 0

lOó REM _END-OF-FILE ERROR _PROCESSING

105

...

0 0 0

130 REM _l/O ERROR _PROCESSING

135

...

An _{error in the} READ

statement of

_line

10 causes execution to

_divert

to the

EXIT _{statement of}

_line

20. Here _{the various error conditions are handled.}

Besides making _the READ

statement simpler, the EXIT _{statement can} be used by

other _{I/O statements for error branching to}

_line

20.

FUR _{var=num-expr I TO nuin-expr} 2 {STEP _num-expr 3}

0 e D

included DeltaBASIC _staternents

e e *

NEXT _var

The FOR/NEXT _{statements set up a loop that performs the included} DeltaBASIC

statements one _or more times, depending on the beginning value of the index

variable (num-expr

_I),

ending value (num-expr 2), and _{the step size (nurn-expr}

3).

_If

_{not specified,} the step size

_is

_l.

The _included DeltaBASIC _statements

_will

be _{executed at least one time before}

termination conditions _are checked. The

_"exit"

_{value of the index variable}

will

be _the

_first

_{value that meets or} exceeds _num-expr2.

FOR/NEXT _{loops can} be _{nested to a level of} 8 deep.

Exiting a FOR/NEXT loop before normal termination

_is

allowed but not

recommended. Repeated _{exits of}

_this

_type

_will

_{cause the} maximum FOR/NEXT

level to be exceeded. Examples: 10 FOR _INDEX=1 to 20 STEP 2 20 PRINT INDEX 30 NEXT INDEX

These FOR/NEXT _{statements cause}

_line

20 _to be _executed 10 _times,

_printing

_the

values from 1

to 19 in steps of 2. The

_"exit"

_{value of} INDEX

_is

21.

FORM _{specification}

list

The FORM

statement gives the format specification

for

PRINT, READ, WRITE, and

REWRITE _statements. The _{specification}

_list

can consist of any combination of

the following specifications, separated by _commas:

"char-cnst"

Character constant: the character

_string

between _{the quotation} marks

_is

output at the current position. Allowed in PRINT and WRITE _only.

C _w

Character

_field:

the matching character value

_is

treated as a character

string that

_{is left-justified}

in a blank

field

of width w. CUR(m,n)

Cursor: the next value

will

be _{output at}

_line

m and position _n. Allowed in

PRINT _only.

N _w{.d)

Numeric

_field:

_{the matching numeric value}

_is

_{treated as a character}

_string

_of

width w, including d decimal positions. For output, the width must include

both a sign and decimal point position. For input, an

explicit

decimal

overrides the

_implicit

decimal position d.

PI) w.d

Packed _{decimal: the matching numeric value}

_is

_{given in} packed _{decimal format.}

For output, the value

_is

rounded _to d _{decimal places, then} packed two binary

coded _decimal

_digits

_{per position} and _written

_{right-justified}

_{into a}

_field

_of

width w. Only the low nibble of the leftmost position contains a

digit.

The

high nibble

_is

0000 _binary

_for

_{a positive value} and 1000 _binary

_for

_a

negative. As _{with zone decimal, no}

_explicit

_decimal

_{is written.}

For _input,

the value

_is

read from a

field

w wide and then given d decimal positions.

Packed _decimal

_is

_{not allowed in the} PRINT _statement.

PIC(char-str)

Picture: the matching numeric value

_is

written into a

field

with width and

composition given by _{the character}

_string.

_{Valid characters are described}

below:

#

Number

_digit:

_{always replaced} by _a

_digit.

Z

Leading zero: any leading _{zero replaced} by _{a blank.}

$

Leading

_dollar

sign:

_dollar

sign placed to the

_left

of the

_first

_nonzero

In document Alternativa pedagógica para el desarrollo de la Educación Ambiental a través de las asignaturas priorizadas en los escolares de quinto grado (página 49-53)