C program alpha and digit..

[aquilina]

I wanna asking about c program that related checking input weather its alpha or digit.. for exampla switch case i declared int.. when i input a alpha, it will give an error message.. how i can do or what code i can use to do such things?

[twomers]

isalpha - C++ Reference
isdigit - C++ Reference

[aquilina]

isalpha - C++ Reference
isdigit - C++ Reference

thank for the info i will check it out.. hope theres no problem when run it at VB for the c program