15-100 Sections S-V / Fall 2008
Quiz 4 / 4 Questions / 30 Minutes
Quiz Date: Tue 30-Sep-2008
1.
What will the following code snippets print?
a.
System.out.println(Math.log(1));
System.out.println(Math.log(-1));
b.
System.out.println("ABCDBC".lastIndexOf("BC",4));
System.out.println("ABCDBC".lastIndexOf("BC",0));
c.
System.out.println("ABCD".substring(1,3));
System.out.println("ABCD".substring(2));
d.
String s1 =
" ab cd ";
String s2 = s1.trim();
System.out.println("[" + s1 + "]");
System.out.println("[" + s2 + "]");
e.
System.out.println(Math.round(-2.50));
System.out.println(Math.floor(2.99));
2.
What will the following code snippets paint?Draw your answer inside the
100x100 window provided for you to the left of each problem. Do not worry about
being pixel-perfect. Within a few pixels is fine.
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a.
page.drawRect(10, 60, 40, 40);
page.drawLine(10, 60, 40, 40);
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b.
int startAngle = -90;
int extentAngle = 180;
page.fillArc(0, 50, 100, 50, startAngle, extentAngle);
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c.
Polygon p = new Polygon();
p.addPoint(50, 0);
p.addPoint(0, 50);
p.addPoint(50, 100);
page.drawPolygon(p);
p.addPoint(100,50);
page.drawPolygon(p);
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d.
Polygon p = new Polygon();
p.addPoint(0, 0);
p.addPoint(50, 50);
p.addPoint(100, 0);
page.fillPolygon(p);
p.translate(0, 50);
page.drawPolygon(p); |
3.
In general, for non-null String s, when would the following expressions
evaluate to true?
a.
(s.indexOf("abc")
== s.lastIndexOf("abc"))
b.
(s.replace("abc","").equals("abc"))
c.
(s.toUpperCase().substring(3).equals(s.toLowerCase().substring(0,3)))
d.
((s+s).length()
== (int)Math.log10(Color.red.getRed()))
4.
Write a method that takes an
integer and returns true if that number is triangular, and false
otherwise, where a number is triangular if it is the sum of the first K positive
integers (for any K>0). The first few triangular numbers are: 1, 3 (1+2),
6 (1+2+3), and 10 (1+2+3+4).
carpe diem -
carpe diem - carpe diem - carpe diem
- carpe diem - carpe diem -
carpe diem - carpe diem - carpe
diem