You are putting the sprintf() statement outside a block of code. Move it to setup().
If you declare variables outside a block of code, it is a global variable. Code must exist inside a function. There is no such thing as 'global' code.
You are putting the sprintf() statement outside a block of code. Move it to setup().
If you declare variables outside a block of code, it is a global variable. Code must exist inside a function. There is no such thing as 'global' code.