$*13\mathrm{.}1($Create a text file$)$ Write a program to create a file named Exercise$13\_1.$txt

if it does not exist. If it does exist, append new data to it$.$ Write $100$ integers

created randomly into the file using text I$/$O$.$ Integers are separated by a space.

$*13\mathrm{.}2($Count characters$)$ Write a program that prompts the user to enter a file

name and displays the number of characters in the file.

C$++$