public/subjects/devops/joker-num/README.md

joker-num

Instructions

In this exercise you are going to create a guessing game. Create the script joker-num.sh which will receive the number to guess as argument. The number should be between 1 and 100 (inclusive). The player will then have 5 tries to guess the number. To achieve this you will have to use a for loop.

When you're trying to guess the secret number with a valid input, your program must output some tips as follow:

• First you will need to prompt a message so that the player knows what he must do: "Enter your guess (<tries_left> tries left).
• If the number is bigger than the secret one: Go down.
• If the number si smaller than the secret one: Go up.
• If the number is the correct one: Congratulations, you found the number in <number_of_tries> moves!.
• If you ran out of tries: You lost, the number was <number>.

Usage

$ ./joker-num.sh 55
Enter your guess (5 tries left):
50
Go up
Enter your guess (4 tries left):
75
Go down
Enter your guess (3 tries left):
55
Congratulations, you found the number in 3 moves!
$ ./joker-num.sh 70
Enter your guess (5 tries left):
70
Congratulations, you found the number in 1 moves!
$

Error handling

• If the player enters the wrong number of arguments or the number is not between 1 and 100, the program will print Error: wrong argument and exit with 1.
• If the player is writing something that is not a valid number as an answer, the program will ask again to enter a new a guess and the number of tries won't be decremented.

Here an example for the last scenario:

$ ./joker-num.sh 100
Enter your guess (5 tries left):
aaaa
Enter your guess (5 tries left):
                                    # Here the player only press enter
Enter your guess (5 tries left):
10
Go up
Enter your guess (4 tries left):
20
Go up
Enter your guess (3 tries left):
10000
Enter your guess (3 tries left):
30
Go up
Enter your guess (2 tries left):
40
Go up
Enter your guess (1 tries left):
50
Go up
You lost, the number was 100

Hints

• read: this command can be used to read input from the command line.

For example:

$ read guess

After running that line, you would type your guess, press Enter, and it would be stored in the $guess variable for later use.

• if [[ -z "$var" ]]: could be helpful to check if a string is empty.