void Library::sortBooks$()$ const

$\{$

std::sort$($books$.$begin$(),$ books.end$(),$

$[]($const Book& pr$,$ const Book& rpr$)$

$\{$return pr$.$getBookTitle$()<$ rpr$.$getBookTitle$()$; $\})$;

$\}$

returns two errors, c$2664$ with the description 'bool Library::sortBooks::::operator$()($const Book&$,$ const Book&$)$ const': cannot convert argument $1$ from 'char' to 'const Book&$\text{'}$ in the file xutility line $1372$ twice, and the same error in the file algorithm, lines $7984,7988,7999,8013,$ The algorithm file is only used to sort the books, and the xutility file isnt used at all in my project so i dont understand why it is giving me errors. any help is appreciated.