Array in Java - Quiz

Which will legally declare, construct, and initialize an array?
  • A int [] myList = {};
  • B int [] myList = (5, 8, 2);
  • C int myList [] [] = {4,9,7,0};
  • D int myList [] = {4, 3, 7};

In Java arrays are
  • A objects
  • B object references
  • C primitive data type
  • D None of the above

What would be the result of attempting to compile and run the following code? 
public class HelloWorld{
      public static void main(String[] args){
            double[] x = new double[]{1, 2, 3};
            System.out.println("Value is " + x[1]);
      }
}

  • A The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by {1, 2, 3}.
  • B The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[3]{1, 2, 3};
  • C The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[]{1.0, 2.0, 3.0};
  • D The program compiles and runs fine and the output

Determine output: 
public class Test{
        public static void main(String[] args){
                int[] x = {1, 2, 3, 4};
                int[] y = x;

                x = new int[2];

                for(int i = 0; i < x.length; i++)
                        System.out.print(y[i] + " ");
        }
}

  • A 1 2 3 4
  • B 0 0 0 0
  • C 1 2
  • D 0 0

Which of these operators is used to allocate memory to array variable in Java?
  • A malloc
  • B alloc
  • C new
  • D new malloc

What will be the output of the program? 
public class Test{
      public static void main(String [] args){
            String s1 = args[1];
            String s2 = args[2];
            String s3 = args[3];
            String s4 = args[4];
            System.out.print(" args[2] = " + s2);
      }
}
and the command-line invocation is C:Java> java Test 1 2 3 4
  • A args[2] = 2
  • B args[2] = 3
  • C args[2] = null
  • D An exception is thrown at runtime.

What will be the output? 
public class Test{
        public static void main(String[] args){
                int[] x = new int[3];
                System.out.println("x[0] is " + x[0]);
        }
}

  • A The program has a compile error because the size of the array wasn't specified when declaring the array.
  • B The program has a runtime error because the array elements are not initialized.
  • C The program runs fine and displays x[0] is 0.
  • D The program has a runtime error because the array element x[0] is not defined.

Analyze the following code and choose the correct answer. 
int[] arr = new int[5];
arr = new int[6];

  • A The code has compile errors because the variable arr cannot be changed once it is assigned.
  • B The code has runtime errors because the variable arr cannot be changed once it is assigned.
  • C The code can compile and run fine. The second line assigns a new array to arr.
  • D The code has compile errors because we cannot assign a different size array to arr.

Which one of the following is a valid statement?
  • A char[] c = new char();
  • B char[] c = new char[5];
  • C char[] c = new char(4);
  • D char[] c = new char[];

What is the result of compiling and running the following code? 
public class Test{
        public static void main(String[] args){
                int[] a = new int[0];
                System.out.print(a.length);
        }
}

  • A 0
  • B Compilation error, arrays cannot be initialized to zero size.
  • C Compilation error, it is a.length() not a.length
  • D None of the above