There are a number of ways to test it. One of them is the val procedure
for further information check out faq218-360 in the pascal-forum about strings
Val( TextVal, Number , Code) converts a string to a number.
If this is possible the result of code = 0, other wise code indicates the character where
the error occured
example:
Textval := '354';
Val(Textval, Number, Code) ---> Code = 0, Number = 354
Textval := '37645x2';
Val( Textval, Number, Code) ---> Code = 6, Number remains unchanged;
Regards
S. van Els
SAvanEls@cq-link.sr