LENGTH_ARRAY on Structure array

papadouk

Having the following code:

DEFINE_STRUCTURE
STRUCTURE TMyStruct
{
  CHAR cStr1[10];
  CHAR cStr2[5];
}

DEFINE_VARIABLE
TMyStruct MyStruct[3];

DEFINE_START
MyStruct[1].cStr1 = 'Test1';
MyStruct[1].cStr2 = '^^';

when i use LENGTH_ARRAY(MyStruct) i get always zero. I was expected to have a value of 1 but...nope.
Now i have to find the active length either by looping through the array or by keeping an index.

Another thing with arrays is that i cannot Increase the maximum length during run-time. In the Help file, somewhere, is written:
"LENGTH_ARRAY returns the effective length of a dimension of an array: the length set implicitly through array initialization or ARRAY MANIPULATION OPERATIONS (+ and –) or explicitly through a call to SET_LENGTH_ARRAY" which made me think that i could do it.

....i have given up trying to make it happen, so i rest my thoughts in the forum...

Kostas

AMXJeff

papadouk wrote: »

Having the following code:

DEFINE_STRUCTURE
STRUCTURE TMyStruct
{
  CHAR cStr1[10];
  CHAR cStr2[5];
}

DEFINE_VARIABLE
TMyStruct MyStruct[3];

DEFINE_START
MyStruct[1].cStr1 = 'Test1';
MyStruct[1].cStr2 = '^^';

when i use LENGTH_ARRAY(MyStruct) i get always zero. I was expected to have a value of 1 but...nope.
Now i have to find the active length either by looping through the array or by keeping an index.

Another thing with arrays is that i cannot Increase the maximum length during run-time. In the Help file, somewhere, is written:
"LENGTH_ARRAY returns the effective length of a dimension of an array: the length set implicitly through array initialization or ARRAY MANIPULATION OPERATIONS (+ and –) or explicitly through a call to SET_LENGTH_ARRAY" which made me think that i could do it.

....i have given up trying to make it happen, so i rest my thoughts in the forum...

Kostas

In order to use LENGTH_ARRAY, the structure array must have length by using SET_LENGTH_ARRAY. SO... Instead... use MAX_LENGTH_ARRAY. This returns the upper bounds of the array indicating this is the max length the array can be.


On the same front... you must always have a max array length. What you do to expand... is declare the array to the max size you will ever need, and use SET_LENGTH_ARRAY to indicate how much you are using, than you can use LENGTH_ARRAY and virtually expand it by using SET_LENGTH_ARRAY again.

somestruct MyStruct[100];

SET_LENGTH_ARRAY(MyStruct, 10);

length = LENGTH_ARRAY(MyStruct) // length = 10

maxLength = MAX_LENGTH_ARRAY(MyStruct) // maxlength = 100

DHawthorne

If you directly assign values to an array, LENGTH_ARRAY will not return the size of the used portion of the array. It only gets updated when you use a function or string operator to update the array. It's mainly intended for strings. If you set the array bounds to, let's say, 25, then do something like, "srtTestArray = 'test string'", then run LENGTH_ARRAY, you'll get 11. If you subsequently run SET_LENGTH_ARRAY(strTestArray, 4), your array will now have the value 'test' in any string operation you run on it ... but if you looked at strTestArray[6], you would see the 's' is still there.

So, in effect, these functions don't deal with the absolute values in the array, but the effective ones.

papadouk

Thank you Jeff and Dave (in order of appearance).

All the things you described are included in the way i work with arrays. It has been like this since i step my foot in the deep waters of Netlinx. It just hit me one of these days to get the active length of a struct by using LENGTH_ARRAY instead of the pre - mentioned ways...It didn't work, so i'm back in my hole.

About the Dynamic growing of an array (beyond the MAX length of it's declaration) was a 'C' programming artifact that hounded me..