may i know how to solve this error ?

 

What about the text that follows it is not clear enough for you? Where are you having a problem?

 

The solution is spelled out in the error message.

 

new error still not solve

 

Did you try the new suggestion?

 

how to try ?

 

how to try ?

It says to use _strupr_s and _strlwr_s

 

Its not an error... That's a warning.. Post the entire build text so we can see the "actual" error..
depreciation wont stop the compile, the compier is just telling you to use the newer library functions. If you use those functions it will still work.
Ergo, I'm assuming something else is wrong!