use c++ to write the program

Extra Write a program that merges the numbers in two files and writes all the numbers into a third file Credit - Merge Sorted Numbers (25 points) kes input from two different files and writes its output to a third file. Each input tile contains a list of numbers of type int in sorted order from the smallest to the largest. After the program is run, the output file will contain all the numbers in the two input files in one longer list in sorted order from smallest to largest. Your program should define at least one function that is called with the two input-file streams and the output-file stream as three arguments. The list of numbers are not necessary of the same length. Aske the user for each file name and test if the file exit. Show the content of all three files on a screen Sample input file 1: 500 Sample input file 2: 101 Sample output file: 101 500 Sample output screen