ANSWERS C Sc 227 Practice Test 1 Fall 2006
Complete this BEFORE your next section. Note: I did not time this test. It should take you longer than 50 minutes.
1. Write a checkmark Ö to the right of any assertion if it would pass. Leave the line in the comment blank
if the assertion would fail (8pts)
assertEquals(2, j / k); // a. ______
assertEquals(1, j % k); // b. ______
assertEquals(-0.5, x + 1, 1e-12); // c. ___Ö___
assertEquals('U', s.charAt(1)); // d. ______
assertEquals(5, s.indexOf("Arizona")); // e. __Ö____
assertEquals(0, s.indexOf("U of A")); // f. ___Ö___
assertTrue(s.compareTo("ASU") > 0); // g. ____Ö__
assertEquals(2.0, Math.sqrt(j), 1e-12); // h. ______
2. Complete the unit test for method grade (fill in the blanks) so it executes every branch of code in the
nested
assertEquals( "A", grade(90.0) ); // or some argument > 90.
assertEquals( "B", grade(80.0) ); // or some argument > 80.0 and < 90.0
assertEquals( "C", grade(70.0) );
assertEquals( "D", grade(60.0) );
assertEquals( "E", grade(50.0) );
3. How many times will the following code print "Hello"? 0, Unknown, and Infinite are legitimate answers
int j = 1;
int n = 5;
while(j <= n) {
System.out.print("Hello");
n++;} Infinite
int j = 1;
while(j <= 11) {
System.out.print("Hello");
j = j + 3;
} 4
int n = 0;
for(int j = 1; j < n; j++) {
System.out.print("Hello");
} Zero
// Tricky Question
for(int j = 1; j <= 11; j++);
System.out.print("Hello"); 1
5. Write a for loop that prints this sequence of integers: -10 –5 0 5 10 15, … , 5555 (6pts)
for (int j = -10; j <= 5555; j = j + 5)
System.out.print (j + " ");
6. Write method occurencesOf that returns the number of times a particular int is found in the Scanner
public void testOccurences() {
Scanner scanner = new Scanner("1 2 3 4 1 2 3 1 6");
assertEquals(3, occurencesOf(1, scanner));
// Need to construct a new Scanner each time. Why?
scanner = new Scanner("1 2 3 4 1 2 3 1 6");
assertEquals(2, occurencesOf(3, scanner));
scanner = new Scanner("1 2 3 4 1 2 3 1 6");
assertEquals(1, occurencesOf(6, scanner)); …
}
public int occurencesOf(int search, Scanner scanner) {
int result = 0;
while (scanner.hasNextInt()) {
if (scanner.nextInt() == search)
result++;
}
return result;
}
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