Key to CSE142 Midterm, Autumn 2012         

1.      Expression                             Value
        -----------------------------------------------    
        5 + 2 * 6 - 10 * 2                     -3
        7 % (5 % 3) + 21 % 4                   2
        2 * 7 + 2 + "*" + 2 + 3                "16*23"
        !(2 < 4 && 5 > 7) && 16 % 4 == 1       false
        107 / 20 * 2 / 3 / 2.0 + 3 / 4.0       2.25

2. Parameter Mystery.  The program produces the following output.

steph wants to play   on the sun
play  wants to steph  on the swim
julie wants to meplay on the play
me    wants to sun    on the sun 

3.      Method Call             Output Produced
        ---------------------------------------
        ifElseMystery(3, 1);    13 1 2
        ifElseMystery(2, 6);    12 6 3 
        ifElseMystery(5, -1);   5 9 5
        ifElseMystery(1, 2);    1 12 4   
        
4.      Method Call             Output Produced
        ---------------------------------------
        mystery(5, 4);          4, 9
        mystery(6, 8);          8, 14, 21
        mystery(3, 6);          6, 9, 13
        mystery(1, 5);          5, 6, 8, 11
        
5.                 x < 5              	  x == 0                z > 0
            +---------------------+---------------------+---------------------+
    Point A | sometimes           | sometimes           | never               |
            +---------------------+---------------------+---------------------+
    Point B | sometimes           | never               | sometimes           |
            +---------------------+---------------------+---------------------+
    Point C | always              | never               | always              |
            +---------------------+---------------------+---------------------+
    Point D | sometimes           | sometimes           | sometimes           |
            +---------------------+---------------------+---------------------+
    Point E | always              | always              | sometimes           |
            +---------------------+---------------------+---------------------+    

6. Three possible solutions appear below:

public static int minOfThree(int a, int b, int c) {
   if (a < b && a < c) {
      return 1;
   } else if (b < a && b < c) {
      return 2;
   } else if (c < a && c < b) {
      return 3;
   } else {
      return -1;
   }
}

public static int minOfThree(int a, int b, int c) {
   if ((a == b && c >= a) || (a == c && b >= c) || (b == c && a >= b)) {
      return -1;
   } else {
      int p = 1;
      int s = a;
      if (b < s) {
         p = 2;
         s = b;
      }
      
      if (c < s) {
         p = 3;
         s = c;
      }
      return p;
   }
}

public static int minOfThree(int x, int y, int z) {
   boolean repeat = false;
   int minPos = 1;
   int minNum = x;
   
   if (y < minNum) {
      minNum = y;
      minPos = 2;
   } else if (y == minNum) {
      repeat = true;
   }
   
   if (z < minNum) {
      minNum = 2;
      minPos = 3;
      repeat = false;
   } else if (z == minNum) {
      repeat = true;
   }
   
   if (repeat == true) {
      return -1;
   } else {
      return minPos;
   }
}

7. One possible solution appears below:

public static void evens(Scanner console, int target) {
   int even = 0;
   int count = 0;
   while (even < target) {
      System.out.print("number? ");
      int val = console.nextInt();
      count++;
      
      if (val % 2 == 0) {
         even++;
      } else {
         even = 0;
      }
   }
   System.out.println(target + " even in a row after " + count + " tries.");
} 

8. Three possible solutions appears below:

public static int countWords(String s) {
   int count = 0;
   boolean inWord = false;
   for (int i = 0; i < s.length(); i++) {
      if (s.charAt(i) == ' ') {
         inWord = false;
      }      else if (!inWord) {
         count++;
         inWord = true;
      }
      return count;
   }
}

public static int countWords(String s) {
   int count = 0;
   for (int i = 1; i < s.length(); i++) {
      if (s.charAt(i - 1) == ' ' && s.charAt(i) != ' ') {
         count++;
      }
   }
   if (s.length() > 0 && s.charAt(0) != ' ') {
      count++;
   }
   return count;
}

public static int countWords(String s) {
   int count = 0;
   int i = 0;
   while (i < s.length()) {
      while (i < s.length() && s.charAt(i) == ' ') {
         i++;
      }
      if (i < s.length()) {
         count++;
         while (i < s.length() && s.charAt(i) != ' ') {
            i++;
         }
      }
   }
   return count;
}