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Key to CSE142 Midterm, Fall 2004 handout #20
Note: Different versions of the test had slightly different orders for
the subparts of questions 1-4. Each test had the same subparts, but they
appeared in slightly different orders.
1. Expression Value
-----------------------------------------------
208 % 10 - 90 % 55 % 10 3
31 % 8/3 * 1.2 2.4
203/10/2.0/4 2.5
79 % (14/3) - 6 * 7/3 -11
2 + 3 + "-" + 8 * 2 + 3 * 4 5-1612
2. Parameter Mystery. The program produces the following output.
students in the beer = 12
beers in the dorm = 125
students in the dorm = 250
beers in the student = 4
students in the classroom = 24
3. Method Call Value Returned
--------------------------------------
mystery(976, 9235) 9
mystery(348, 34298) 34
mystery(2974, 2184) 2
mystery(82, 19) 0
mystery(2348, 239) 23
4. x > y z > 0 y % 2 == 0
+---------------------+---------------------+---------------------+
Point A | sometimes | never | never |
+---------------------+---------------------+---------------------+
Point B | always | sometimes | sometimes |
+---------------------+---------------------+---------------------+
Point C | sometimes | always | sometimes |
+---------------------+---------------------+---------------------+
Point D | sometimes | always | always |
+---------------------+---------------------+---------------------+
Point E | never | sometimes | sometimes |
+---------------------+---------------------+---------------------+
5. Three possible solutions appear below.
public static void betOnce(Scanner console, int number) {
System.out.print("Do you want to bet on 1) low or 2) high? ");
int bet = console.nextInt();
System.out.println("The number was " + number);
if (bet == 1)
if (number == 0)
System.out.println("You lose");
else if (number <= 18)
System.out.println("You win");
else
System.out.println("You lose");
else
if (number > 18)
System.out.println("You win");
else
System.out.println("You lose");
}
public static void betOnce(Scanner console, int number) {
System.out.print("Do you want to bet on 1) low or 2) high? ");
int bet = console.nextInt();
System.out.println("The number was " + number);
if (number == 0)
System.out.println("You lose");
else if ((bet == 1 && number <= 18) || (bet == 2 && number > 18))
System.out.println("You win");
else
System.out.println("You lose");
}
public static void betOnce(Scanner console, int number) {
System.out.print("Do you want to bet on 1) low or 2) high? ");
int bet = console.nextInt();
System.out.println("The number was " + number);
int result = (number - 1)/18 + 1;
if (number != 0 && result == bet)
System.out.println("You win");
else
System.out.println("You lose");
}
6 One possible solution appears below.
public static double sumTo(int n) {
double sum = 0.0;
for (int i = 1; i <= n; i++)
sum = sum + 1.0/i;
return sum;
}
7. One possible solution appears below.
public static int digitSum(int n) {
int sum = 0;
while (n > 0) {
sum += n % 10;
n /= 10;
}
return sum;
}
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