Kanchi 

                  CPSC 101 COMPUTING AND ALGORITHMS I 

                                TEST I 

Your Name: KEY 
          --------------------------------


1. (15 points) State True or False. Give reasons for your choice. 

A. The Java compiler works more efficiently if the looping
   statements are properly indented. 
   
   Answer: 
   False. The amount of indentation is irrelevant to java compiler.
   Java is free format.


B. A memory is said to be a ROM if every address is a random number.  

   Answer: 
   False. ROM refers to the fact that the memmory cannot be written 
   onto. It is a read only memory.



C. If a is a char type whose value is '9' and b is an int
   type whose value is 9, then the contents in the memory of a and b 
   will be the same. 

   Answer: 
   False. The unicode value of '9' is stored for char type. However, 
   for int type the value is 9 is stored. Moreover the number of 
   bits reserved may also vary for int and char types. 
   

D. Given that x is  declared as a boolean, the assignment statement

        x = false || true; 

   will store the value 'true' in x. 

   Answer: 
   True, x will be 'true' since the right side evaluates to 'true' value.



E. Assuming that ReadUtility is available, the code,

    int x; 
    x = (int) 14.5 + 3.5;
 
  will cause errors. 
   
  Answer:
    True. 14.5 is converted to int first which makes it 14 and then 3.5 is added
    which makes it double value of 17.5 and this cannot be assigned to an int x. 


2. (20 points) Find errors (compile time, run time and logical), if any,  
   in following codes and explain the errors. Skip the error 
   prone statements and continue with the rest of the code. 
   Show the output of the error free lines. 
   
   (Note: Do not look for missing statements, simply examine the 
   given code for errors.)



A.   int x = 5; 

     if (x == x+1) {
        System.out.println("yes");
     }
     else
        System.out.println("No"); 


   Answer: 
   No Errors. The printout is 
              No


B.   int x = 65;                \\Line 1
     float f = 65.5f;           \\Line 2
     char c = 'B';             \\Line 3
     
     f = x;                    \\Line 4
     x = f;                    \\Line 5 
     c = (char) x;             \\Line 6 
     x = c;                    \\Line 7
     c = (char) f;             \\Line 8 
     f = (char) c;             \\Line 9

    System.out.println(c);      \\Line 10
    System.out.println(f);      \\Line 11
    System.out.println(x);      \\Line 12
    
   Answer: 

     Error in Line 5, since x is int and f is float, it is a 
     windening convention. 
     Printout: A
               66.0
               66
                


3.(20 points) For each of the expressions below, find the value and 
    state any changes to memory. Identify any invalid expressions and 
    explain why it is invalid. 

     a)   int x = 4, y = 3; 
          boolean d; 
        
       d = x==3 % y || !false 

    Answer 

      d = x == 3 % y  || true 
      d = x == 0  || true 
      d = false || true 
      d = false || true 
      d = true
      true 

      Note: Side effect d becomes true. 







     
     b)  float q=9.0f, r= 4.3f;
   
          q = q+1 * 3 % 2  -r 

       Answer:

          q = q+ 3 % 2  -r 
          q = q+1  -r 
          q = 10.0  -r 
          q = 10.0  - 4.3 
          q = 5.7 
            5.7

         Note: Side Effect is that q changes to 5.7.

4. (15 points)  Use a if statement to read a character and 
    
   if it is 'W' or 'w' -- print WINDOW 
   if it is 'A' or 'a' -- print AISLE
   else -- print NOT VALID 

   Answer:
  
     char c;
     c = ReadUtility.readChar();

     if (c == 'w' || c == "W') 
      System.out.println("WINDOW");
     else
        if (c == 'A' || c == 'a')
          System.out.println("AISLE");
        else 
          System.out.println("NOT VALID");



5. (30 points) Write a program that reads weight and height  
   and prints if person is overweight.
   
   A valid weight must be between 50 pounds and 450 pounds 
   and valid height must be between 4 feet and 7 feet. 
   If an invalid entry is read, the program exits. 
   
   The program computes if the person is overweight using the 
   following rule: 
   If a person's weight is more than height times 50,  
   then that person is considered overweight. 

   Make sure weight and height are 'float's not 'int's! 
   Use constants wherever appropriate.

   Sample Run1: Enter weight: 340.0
                Enter height: 5.0
    
                YOU ARE OVERWEIGHT.. YOU ARE OVER 250 pounds!!


   Sample Run2: Enter weight: 140.0
                Enter height: 5.0

                YOU ARE NOT OVERWEIGHT.. YOU ARE UNDER 250 pounds!!

   Sample Run3: Enter weight: 740.0
                Enter height: 6.0
           
               YOUR WEIGHT OR HEIGHT IS INVALID 
   Answer: 

  import ReadUtility;
  class MainClass{

   public static void main(String[] args){


    float LOW_WEIGHT_LIMIT = 50.0f;
    float HIGH_WEIGHT_LIMIT = 450.0f;

    float LOW_HEIGHT_LIMIT = 4.0f;
    float HIGH_HEIGHT_LIMIT = 7.0f;

    float FACTOR = 50.0f;
    int NUM_TIMES = 8;
    int choice;
    int height; 
    int weight; 
  
       System.out.print("Enter weight:" );
       weight = ReadUtility.readFloat();
   
       System.out.print("Enter height:");
       height = ReadUtility.readFloat();
       
       if (weight < LOW_WEIGHT_LIMIT  || weight > HIGH_WEIGHT_LIMIT || 
            height<IGH_LIMIT  || height > HIGH_HEIGHT_LIMIT) 
           System.out.println("INVALID WEIGHT OR HEIGHT");
       } 
       else 
 
           if (weight > height *FACTOR) 
               System.out.println("YOU ARE OVERWRIGHT ... YOU ARE OVER" + 
                height*FACTOR +"POUNDS");
       else
             System.out.println("YOU ARE NOT OVERWEIGHT.. YOU ARE UNDER" +
          height*FACTOR + "POUNDS");
  
  } //end main
}//end MainClass