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Key to CSE143X Sample Midterm, Fall 2018 handout #9
1. Expression Value
-----------------------------------------------
5 * 6 - (4 + 3) * 2 - 2 * 3 10
208 / 20 / 4 + 12 / 10.0 + 0.4 * 2 4.0
8 - 2 + "8 - 2" + 8 * 2 + 8 "68 - 2168"
4 * 5 % 6 + 297 % 10 + 4 % 8 13
13 / 2 * 3.0 + 5.5 * 3 / 2 26.25
2. Parameter Mystery. The program produces the following output.
picnic and lemonade like ants
ants and ants like y
lemonadey and antspicnic like antsy
lemonade and sunny like today
3. Method Call Output Produced
---------------------------------------
ifElseMystery(5, 20); 7 5
ifElseMystery(42, 42); 43 41
ifElseMystery(6, 1); 9 7
ifElseMystery(2, 0); 3 -1
ifElseMystery(7, 10); 9 7
ifElseMystery(4, 4); 5 3
4. Method Call Output Produced
---------------------------------------
mystery(8); 1 8
mystery(32); 2 5
mystery(184); 3 13
mystery(8239); 4 22
5. y == 0 y % 2 == 0 z == 0
+---------------------+---------------------+---------------------+
Point A | never | always | always |
+---------------------+---------------------+---------------------+
Point B | never | always | sometimes |
+---------------------+---------------------+---------------------+
Point C | sometimes | always | never |
+---------------------+---------------------+---------------------+
Point D | never | never | sometimes |
+---------------------+---------------------+---------------------+
Point E | always | always | sometimes |
+---------------------+---------------------+---------------------+
6. One possible solution appears below.
public static int printSequenceTo(double value) {
double sum = 0.5;
System.out.print("1/2");
int n = 1;
while (sum < value) {
n++;
System.out.print(" + " + n + "/" + (n + 1));
sum = sum + (double) n / (n + 1);
}
System.out.println(" = " + sum);
return n;
}
7. One possible solution appears below.
public static void switchData(Scanner input) {
while (input.hasNextLine()) {
String line = input.nextLine();
Scanner tokens = new Scanner(line);
String label = tokens.next();
System.out.print(label);
while (tokens.hasNextInt()) {
int n1 = tokens.nextInt();
if (tokens.hasNextInt()) {
int n2 = tokens.nextInt();
System.out.print(" " + n2);
}
System.out.print(" " + n1);
}
System.out.println();
}
}
8. Arrays. One possible solution appears below.
public static void minToFront(int[] list) {
if (list.length > 0) {
int min = 0;
for (int i = 0; i < list.length; i++) {
if (list[i] < list[min]) {
min = i;
}
}
int temp = list[0];
list[0] = list[min];
list[min] = temp;
}
}
9. Programming. One possible solution appears below.
public static boolean isMatch(String pattern, String text) {
int j = 0;
for (int i = 0; i < pattern.length(); i++) {
char ch1 = pattern.charAt(i);
if (ch1 == '*') {
int diff = text.length() - pattern.length() + 1;
if (diff < 0) {
return false;
} else {
j += diff;
}
} else {
if (j >= text.length()) {
return false;
}
char ch2 = text.charAt(j);
j++;
if (ch1 != '.' && ch1 != ch2) {
return false;
}
}
}
return j == text.length();
}
below is a solution to the 4-point problem:
public static boolean isMatch(String pattern, String text) {
if (text.length() != pattern.length()) {
return false;
}
for (int i = 0; i < pattern.length(); i++) {
char ch1 = pattern.charAt(i);
char ch2 = text.charAt(i);
if (ch1 != '.' && ch1 != ch2) {
return false;
}
}
return true;
}
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