How to check for numbers and other specials. operations?

Question

C++ / C#

How to check for char in pluses to determine what kind of character. For example, if the character type is a digit, how do I know if it's a digit or a letter? This is necessary for the drug analyzer.

Answer 1

en.cppreference.com/w/c/string/byte/isdigit
en.cppreference.com/w/cpp/string/byte/isdigit

Answer 2

For example, if the character type is a digit, how do I know if it's a digit or a letter?

Try to learn how to ask questions in such a way that the people you ask them can understand them, preferably unambiguously. This will help both you and those you ask.
Characters are bytes, they can be simply compared. For example
if (c == '1')
if (c >= 'a' && c <= 'z')
In addition, there is a family of is* classifier functions declared in <ctype.h>/<cctype> . They classify characters based on the current locale.