In this homework, you will write a program that reads in two positive integers that are

$20$ or fewer digits in length and then outputs the sum of the two big integers.

Use the following declaration in your program:

vector bigInt$1(20),$ bigInt$2(20),$ sumBigInt$(20)$;

Your program will read the big integers as strings. After they are read into the

program, each character in the string is changed to a value of type int and stored in

the corresponding vector appropriately. Recall that in the elementary school paper$-$

and$-$pencil addition algorithm, we start adding the digits in the units place first and

then move towards the higher place value. So pay attention to how you will store the

digits in the vector.

Your program will perform the addition by implementing the usual paper$-$and$-$pencil

addition algorithm. The result of the addition is stored in an array of size $20$ and the

result is then written to the screen. If the result of the addition is an integer with more

than the maximum number of digits $($that is$,$ more than $20$ digits$),$ then your program

should issue a message saying that it has encountered "integer overflow". You should

be able to change the maximum length of the integers by changing only one globally

defined constant. Include a loop that allows the user to continue to do as many

additions of $2$ big integers as they prefer until they choose to quit. Use C$++$ programming with using "using namespace std$".$ Make the code simple and not too long. Put the functions under$/$below or after the "int main"