Fall '97 -- Midterm Solutions
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TEST out of 50.  

1. [10 marks]
(a)
    class Person {

       String name;
       double height, weight;

       Person (String name, double height, double weight) {
          this.name = name;
          this.height = height;
          this.weight = weight;
       }

       String toString () {
          return name + " is " + 
                 height + " cm. tall and weighs " + 
                 weight + " kg.";
       }
    }    
(b)
    Person p = new Person("name", 70.5, 80.1);

    
2. [10 marks]

1 for saying compile or run or logical or no error and
the rest of the marks for the explanation.

  (a) int i = 0.1;

    3 marks
    compile time error
    float assigned to an integer

  (b) String s = new String{};

    2 marks
    compile time error
    {} should be ()

  (c) int i = 10;
      int j = 9;
      int k = i / (i - j - 1);

    3 marks
    run time error
    divide by zero

  (d) System.out.println ("one + one = " + (1 * 1));

    2 marks
    logical error 
    no one + one is not = 1

3. [10 marks]

  (a)  	String one = "can ";
	String two = "be, ";
	String three = "don't you think";
	System.out.println("As easy as " + one + two + three);
       
 	As easy as can be, don't you think

  (b)   if (args.length == 1)
	   System.out.println("args[0] = " + args[0]);
	else if (args.length == 2) {
	   System.out.println("args[0] = " + args[0]);
	   System.out.println("args[1] = " + args[1]);}
	else if (args.length == 3) {
	   System.out.println("args[0] = " + args[0]);
	   System.out.println("args[1] = " + args[1]);
	   System.out.println("args[2] = " + args[2]);
	}

        args[0] = my
	args[1] = name
	args[2] = is

  (a)   for (int i = 0; i < args.length;i++)
           System.out.println("args["+i+"] = " + args[i]);

       	int count = 0;
	while (count < 5) {
	   count++;
	   System.out.println (count + " )");
	}

  (d)
        1)
	2)
	3)
	4)
	5)

4. [10 marks]

     1. Give an example of three primitive types and their declarations.
	2 marks for each wrapper class (6 marks).

           int    count = 12;        Also: byte, short, float, ...
           double price = 32.87;
           char   unit  = 'F';
           
     2. Give two examples of wrapper classes and create an instance of each.
	2 marks for each wrapper class (4 marks).
	
	   Double  d = new Double(2.3);    Also: Boolean, Byte, Character, Long,...
	   String  s = new String("name");
	   Float   f = new Float(2.3f);
	   Integer i = new Integer(53);

5. [10 marks]

	double x_Square_Plus_x (double x) {
	   return x*x+x;
	}