would you please explain this line

Development Boards Arduino
1

hey, everyone, I’m going to use an alphabetic keypad for my project bu I couldn’t understand this line of

buildStr[buildCount++] = (isalpha(key)) ? virtKey : key;

i approciate anyone could help me;

many thanks

Abolfazl

2 
buildStr[buildCount++] =
```Here it assigns an element in the array (string?) buildStr at index buildCount to what is evaluated after the equal symbol. After the value is assigned buildCount is also incremented (postfix execution). The content of the array element is determined by the following.

(isalpha(key)) ? virtKey : key;


Since I have no idea what buildCount, the function isalpha, key or virtKey means I can't tell why this is meant to be so. The rest of your program would provide context to this. Based on common naming convetions buildStr is likely a string.
3

thank you, dear, @Valen

this line enough for me!

“This evaluation is a kind of if-statement. If the result of the function isalpha(key) is true, then the result is virtKey, otherwise key.”