Command line execution in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the first command line argument.

Java

public class Main {
    public static void main(String[] args) {
        System.out.println([1]);
    }
}

Drag options to blanks, or click blank then click option'

Aargs.first()

Bargs(0)

Cargs.get(0)

Dargs[0]

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of square brackets to access array elements.

Trying to call methods like get() on the array.

The command line arguments are stored in the args array. To access the first argument, use args[0].

2fill in blank

medium

Complete the code to check if any command line arguments were passed.

Java

public class Main {
    public static void main(String[] args) {
        if ([1] > 0) {
            System.out.println("Arguments received.");
        } else {
            System.out.println("No arguments.");
        }
    }
}

Drag options to blanks, or click blank then click option'

Aargs.length

Bargs.count()

Cargs.size()

Dargs.length()

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() with parentheses which causes a compile error.

Using methods like size() or count() which do not exist for arrays.

The number of command line arguments is given by args.length. It returns the size of the array.

3fill in blank

hard

Fix the error in the code to print all command line arguments separated by spaces.

Java

public class Main {
    public static void main(String[] args) {
        for (int i = 0; i < [1]; i++) {
            System.out.print(args[i] + " ");
        }
    }
}

Drag options to blanks, or click blank then click option'

Aargs.count()

Bargs.size()

Cargs.length

Dargs.length()

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() with parentheses causing errors.

Using size() or count() which are not valid for arrays.

The loop should run while i is less than args.length, which is the number of command line arguments.

4fill in blank

hard

Fill both blanks to print the last command line argument safely.

Java

public class Main {
    public static void main(String[] args) {
        if (args.[1] > 0) {
            System.out.println(args[[2]]);
        } else {
            System.out.println("No arguments.");
        }
    }
}

Drag options to blanks, or click blank then click option'

Alength

Blength()

Csize

Dcount

Elength - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() with parentheses.

Using size or count which are invalid for arrays.

To safely print the last command line argument, first check if args.length > 0. Then access args[args.length - 1] for the last element.

5fill in blank

hard

Fill all three blanks to print all arguments in uppercase separated by commas.

Java

public class Main {
    public static void main(String[] args) {
        for (int [1] = 0; [2] < args.[3]; [1]++) {
            System.out.print(args[[1]].toUpperCase());
            if ([1] < args.length - 1) {
                System.out.print(", ");
            }
        }
    }
}

Drag options to blanks, or click blank then click option'

Ai

Bj

Clength

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using size instead of length for arrays.

Using different variable names inconsistently in the loop.

The loop variable is commonly i. The condition uses args.length to get the number of arguments.