hello i have stuck in one situation on strings i have text consider as follows

Electronic mail, most commonly referred to as email or e-mail since c 1993,[2] is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. ex@ex.in Some early email systems required that the author and the recipient both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need connect only briefly, typically to a mail server, for as long as it takes to send or receive messages. some@email.com Historically, the term electronic mail was used generically for any electronic document transmission. esample@some.in For example, several writers in the early 1970s used the term to describe fax document transmission.[3][4] As a result, it is difficult to find the first citation for the use of the term with the more specific meaning it has today.

in above give text there are 3 emails (ex@ex.in, esample@some.in, some@email.com) i have to find them and replace with XXXXXXXXX for security reasons.

Any suggestions will be helpfull