12.7) Exercise 18
- Start by reminding yourself of how command line arguments work in C++.
- Copy your Exercise 17 solution to a new file. Modify this program by first removing the code that populates the vector with data read from
cin
. In its place, add code that: - Checks that the argument count
argc
is equal to 2, terminating the program with the message "Error: filename required" if this is not the case - Opens a file for input, using argument
argv[1]
as the filename and terminating with the message "Error: cannot open file" if opening the file fails for any reason - Reads numbers from the file and appends them to the vector
- Create a small file containing a list of numbers. Run the program on this file and check that it produces the correct output.