Quote:
2) There might be lot of numeric data to read. and if we each time type out the validateion for the string,then NO code-reuse. .if we create a validation class,and have validate Int,validate string,will that be correct?wrong?
Validation usually is more about just the type of data. Sure, the input is an integer, but maybe it needs to be in the range of 0..10. A string might have to be all lower case. Etc. As the input constraints become more complicated, you are no longer doing just validation, but full-on parsing.