Leica tps1100, Руководство пользователя, Страница: 260 / 1154

GeoBASIC Reference Manual 2.GeoBasic Constructs
TPS1100-Version 1.30 2-31
DIM dSum AS Double 'for the summation
DIM iIndex AS Integer 'the running index
DIM iLastIndex AS Integer 'index of last element
' to add
DIM NumberArray (iMaxIndex) AS Double
'array with the numbers
Then the following WHILE loop sums up iLastIndex (
≤
iMaxIndex )
numbers of the array
NumberArray
. The resulting sum will be in
dSum
.
dSum = 0 'so far the sum is zero
iIndex = 1 'the first index is 1
DO WHILE iIndex <= iLastIndex 'as long as we are
'
not at the end
dSum = dSum + NumberArray(iIndex) 'add the
' current element
iIndex = 1 'compute next index
LOOP
♦
Every
WHILE
loop can be transformed in an equivalent
UNTIL
loop and vice
versa. Have a look at the following
UNTIL
version of the summation.
dSum = 0 'so far the sum is zero
iIndex = 1 'the first index is 1
DO 'loop
dSum = dSum + NumberArray(iIndex) 'add the current
' element
iIndex = 1 'next index
LOOP UNTIL iIndex > iLastIndex 'until we exceed
' the last index
♦
These two loops (the
WHILE
and
UNTIL
version) perform exactly the same
computation for iLastIndex > 0 . But for iLastIndex <= 0 , dSum
remains
0
and
iIndex
remains
1
in the
WHILE
example, while in the
UNTIL
version
dSum
is set to the value of
NumberArray(1)
, and
iIndex
is incremented once.
2.6.3.3 The FOR-Loop
The three
Integer
expressions (
Start
,
Finish
,
Step
) are evaluated at the
outset. If the
Step
part is omitted,
Step
is set to
+1
by default. The values thus
obtained for Finish and Step are used throughout execution of the FOR -loop,