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Key to CSE143X Sample Midterm, Fall 2019 handout #8
1. Expression Value
-----------------------------------------------
3 + 3 * 8 - 2 25
109 % 100 / 2 + 3 * 3 / 2.0 8.5
1 - 3 / 6 * 2.0 + 14 / 5 3.0
1 + "x" + 11 / 10 + " is" + 10 / 2 1x1 is5
10 % 8 * 10 % 8 * 10 % 8 0
2. Parameter Mystery. The program produces the following output.
she can't take she with her
it can't take her with you
you can't take it with you
fred can't take her with him
3. Method Call Output Produced
---------------------------------------
ifElseMystery(5, 15); 7 15
ifElseMystery(12, 5); 12 1
ifElseMystery(7, 8); 8 9
ifElseMystery(2, 3); 4 -2
ifElseMystery(1, -2); 2 -7
ifElseMystery(1, 1); 2 -4
4. Method Call Output Produced
---------------------------------------
mystery(1); 1
mystery(3); 2
mystery(5); 5
mystery(7); 13
5. x > 2 x < n n % x == 0
+---------------------+---------------------+---------------------+
Point A | never | sometimes | sometimes |
+---------------------+---------------------+---------------------+
Point B | sometimes | always | sometimes |
+---------------------+---------------------+---------------------+
Point C | never | sometimes | sometimes |
+---------------------+---------------------+---------------------+
Point D | always | sometimes | sometimes |
+---------------------+---------------------+---------------------+
Point E | sometimes | never | sometimes |
+---------------------+---------------------+---------------------+
6. One possible solution appears below.
public static boolean checkPrime(int n) {
System.out.print("factors of " + n + " = 1");
int count = 1;
for (int i = 2; i <= n; i++) {
if (n % i == 0) {
System.out.print(", " + i);
count++;
}
}
System.out.println();
System.out.println("Total factors = " + count);
return count == 2;
}
7. One possible solution appears below.
public static void printDuplicates(Scanner input) {
String prevToken = input.next();
int count = 1;
while (input.hasNext()) {
String nextToken = input.next();
if (nextToken.equals(prevToken)) {
count++;
} else if (count > 1) {
System.out.println(prevToken + "*" + count + " ");
count = 1;
}
prevToken = nextToken;
}
if (count > 1) {
System.out.println(prevToken + "*" + count + " ");
}
}
8. Arrays. One possible solution appears below.
public static boolean isPairwiseSorted(int[] list) {
for (int i = 0; i < list.length - 1; i += 2) {
if (list[i] > list[i + 1]) {
return false;
}
}
return true;
}
9. Programming. One possible solution appears below.
public static boolean samePattern(String s1, String s2) {
if (s1.length() != s2.length()) {
return false;
}
for (int i = 0; i < s1.length(); i++) {
for (int j = i + 1; j < s1.length(); j++) {
if (s1.charAt(i) == s1.charAt(j) &&
s2.charAt(i) != s2.charAt(j)) {
return false;
}
if (s2.charAt(i) == s2.charAt(j) &&
s1.charAt(i) != s1.charAt(j)) {
return false;
}
}
}
return true;
}
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