Read a $2-$character string from input into variable userString. Declare a Boolean variable isValid and assign isValid with true if the

following conditions are met:

userString does not contain two of the same character.

For alphabetic characters, userString does not contain two of the same letter $($regardless of case$).$

Otherwise, assign isValid with false.

Ex: If the input is $d!,$ then isValid is assigned with true, so the output is:

Valid string

Ex: If the input is $Pp,$ then isValid is assigned with false, so the output is:

Invalid string

Note: Use getline $($cin$,$ userString$)$ to read the entire line from input into userString.

#include $V^{**}$