$1.$ Write a C$++$ function that allows the user to enter a string of characters $($which may or may not rep$-$

resent a valid DNA string$).$ Upon pressing the string should be read from standard input

$($cin$)$ and returned by the function.

$2.$ You should assume that main$()$ calls the function, passing no args. The return type of the function

should be string. The function prototype should be like:

string enterDNAString$()$;

$3.$ The program should echo the string entered, followed by the size of the string $($number of charac$-$

ters$)$ in brackets, for e$.$g$.$ if the user enters $$ABHDKDJ$,$ the program will output:

ABHDKDJ $(7$ chars$)$