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CSE 142 Sample Midterm Exam
1. Expressions
For each expression in the lefthand column, indicate its value in the righthand column.
Be sure to list a constant of appropriate type (e.g., 7.0 rather than 7 for a double, Strings in quotes).
Expression Value 8 + 5 * 3 / 2 _________________________ 1.5 * 4 * 7 / 8 + 3.4 _________________________ 73 % 10 6 % 10 + 28 % 3 _________________________ 4 + 1 + 9 + "." + (3 + 10) + 11 / 3 _________________________ 3 / 14 / 7 / (1.0 * 2) + 10 / 6 _________________________ 10 > 11 == 4 / 3 > 1 _________________________
2. Parameter Mystery
At the bottom of the page, write the output produced by the following program.
public class ParameterMystery { public static void main(String[] args) { String x = "happy"; String y = "pumpkin"; String z = "orange"; String pumpkin = "sleepy"; String orange = "vampire"; orange(y, x, z); orange(x, z, y); orange(pumpkin, z, "y"); z = "green"; orange("x", "pumpkin", z); orange(y, z, orange); } public static void orange(String z, String y, String x) { System.out.println(y + " and " + z + " were " + x); } }
4. While Loop Simulation
For each call of the method below, write the value that is returned:
public static int mystery(int i, int j) { int k = 0; while (i > j) { i = i j; k = k + (i 1); } return k; } Method Call Value Returned mystery(2, 9) _______________________________ mystery(5, 1) _______________________________ mystery(38, 5) _______________________________ mystery(5, 5) _______________________________ mystery(40, 10) _______________________________
5. Assertions
For the following method, identify each of the three assertions in the table below as being either ALWAYS true,
NEVER true or SOMETIMES true / sometimes false at each labeled point in the code. You may abbreviate these
choices as A/N/S respectively.
public static int mystery(Scanner console) { int y = 0; int z = 1; int next = console.nextInt(); // Point A while (next >= 0) { // Point B if (y > z) { // Point C z = y; } y++; next = console.nextInt(); // Point D } // Point E return z; } next < 0 y > z y == 0 Point A Point B Point C Point D Point E
7. Programming
Write a static method named monthApart that accepts four integer parameters representing two calendar dates. Each
date consists of a month (1 through 12) and a day (1 through the number of days in that month [2831]). Assume that
all dates occur during the same year. The method returns whether the dates are at least a month apart. For example,
the following dates are all considered to be at least a month apart from 9/19 (September 19): 2/14, 7/25, 8/2, 8/19,
10/19, 10/20, and 11/5. The following dates are NOT at least a month apart from 9/19: 9/20, 9/28, 10/1, 10/15,
and 10/18. Note that the first date could come before or after (or be the same as) the second date. Assume that all
parameter values passed are valid.
Sample calls:
monthApart( 6, 14, 9, 21) should return true, because June 14 is at least a month before September 21
monthApart( 4, 5, 5, 15) should return true, because April 5 is at least a month before May 15
monthApart( 4, 15, 5, 15) should return true, because April 15 is at least a month before May 15
monthApart( 4, 16, 5, 15) should return false, because April 16 isn't at least a month apart from May 15
monthApart( 6, 14, 6, 8) should return false, because June 14 isn't at least a month apart from June 8
monthApart( 7, 7, 6, 8) should return false, because July 7 isn't at least a month apart from June 8
monthApart( 7, 8, 6, 8) should return true, because July 8 is at least a month after June 8
monthApart(10, 14, 7, 15) should return true, because October 14 is at least a month after July 15
8. Programming
Write a static method named threeHeads that repeatedly flips a coin until three heads in a row are seen. You should
use a Random object to give an equal chance to a head or a tail appearing. Each time the coin is flipped, what is seen
is displayed (H for heads, T for tails). When 3 heads in a row are flipped a congratulatory message is printed. Here
are possible outputs of two calls to threeHeads:
T T T H T H H H Three heads in a row! T H T H T T T T T H H T H H H Three heads in a row!
