hello-cmd – Hello (command line argument) – Computer Science by Example

hello-cmd – Hello (command line argument)

Hello, <You>!

Write a program that produces as hello message in the format Hello, <name>! where <name> is taken as a command line argument.

Example command line session 1

$ ./hello-cmd John
Hello, John!

Example command line session 2

$ ./hello-cmd Mary
Hello, Mary!

Scoring

2/10: produces a “hello” message for the above example test cases
4/10: produces a “hello” message for the above example test cases in the correct format
10/10: produces a “hello” message in the correct format for any name

Hints

In Python, you can access command line arguments in the sys.argv variable. First import sys then use argv[0] to see the program name argv[1] to see the first command line argument, argv[2] to see the second, etc.

In C, you can access command line arguments by declaring main with the following prototype:

int main(int argc, char *argv[])

Above, argc is the count of arguments and argv is an array of strings where argv[0] is the program name, argv[1] is the first command line argument, argv[2] is the second and so on.

In Haskell, you can access command line arguments by using the function System.Environment.getArgs :: IO [String]. First import System.Environment then pull the result of getArgs from the IO monad. The first element of the result will be the program name, the second element will be the first command line argument, the third element will be the second command line argument, and so on.

try first: hi index-ints

try also: erro

try next: errxit

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