$1.$ Write a C$++$ function to check that the DNA string entered using Part I is valid $$ i$.$e$.$ the string only

contains valid nucleotides $($A$|$G$|$T$|$C$).$ These can be repeated any amount of time, but can only be

these characters. There should also be no white spaces in the entered text.

$2.$ The function should accept the original string variable $($from Part I$)$ as an argument $($passed by val$-$

ue$)$ and should return true$/$false as the result $($true if valid$).$ The function prototype should be:

bool checkValidity$($string s$)$;

$3.$ The output to the screen should extend the output of Part I $($as in the following examples$)$:

ABHDKDJ $(7$ chars$)$ : INVALID DNA

AGTC $(4$ chars$)$ : VALID DNA

AgtCCcTa $(8$ chars$)$ : VALID DNA