C$++$ ONLY

Imagine you are developing a feature for a web application that provides users with feedback on the strength of their passwords as they create them. A simple criterion for an initial check on password strength is whether the password starts with a letter. This is a basic requirement before more complex checks are applied. Your task is to implement a piece of code that checks if the first character of a user's password is a letter $($either uppercase or lowercase$).$

Assume password is a variable of type string that has been assigned a value by the user. Write an expression whose value is true if the first character of the value of password is a letter $($uppercase or lowercase$).$ This involves checking if the first character falls within the ranges $\text{'}$A$\text{'}$ to $\text{'}$Z$\text{'}$ or $\text{'}$a$\text{'}$ to $\text{'}$z$\text{'}.$ Save the result to a variable result.