1. CS Week 3
Jim Williams

2. Learning and Effort Influence Intelligence
"...effort and difficulty, that's when their neurons are making new connections, stronger connections. That's when they're getting smarter." - Carol Dweck

3. P1 Milestone 2 due Thursday 8:00am
Week 3
P1 Milestone 2 due Thursday 8:00am
Commenting Example
Exam Confirmation and Accommodation requests due by Friday
CS Learning Center
In CS Building, above entrance to Union South

4. Eclipse IDE (Integrated Development Environment)
Interpreter
Translator
Users
Editor
(Virtual)
Machine
Compiler
Hello.java
Hello.class
Computer
Files
Programmer

5. Programming Errors Syntax/Compile time Runtime & Logic Files
Editor
(Virtual)
Machine
Compiler
Hello.java
Hello.class
Computer
Files
Programmer

6. Programming Errors Syntax compiler error Logic
program runs but provides wrong values
Runtime
program crashes or throws exception

7. Debugging print statements Java Visualizer Breakpoints in Eclipse

8. What is print out? a char choice = 'a'; switch (choice) {
case 'a': System.out.print("a");
case 'b': System.out.print("b");
break;
default: System.out.print("other"); } a b ab
other

9. ? : operator (not recommended)
condition ? <true value> : <false value>
What is out?
String out = "don't know";
boolean sunny = false;
out = sunny ? “sunny” : “cloudy”;
out:don't know
out:sunny
out:cloudy

10. Scanner num: 0 str4: line str4: line note. num: 3 str4:
String note = "Hmm\na 3\nline note.";
Scanner input = new Scanner( note);
int num = 0;
String str1 = input.nextLine();
String str2 = input.next();
if ( input.hasNextInt()) {
num = input.nextInt(); }
String str4 = input.nextLine();

11. char - Which will compile?
1, 2, 3
1, 3 1
2, 3
int intValue = 0;
char aChar = 'B';
intValue = aChar; // 1
aChar = intValue + 1; // 2
aChar = '\u0041'; // 3

12. Increment && Decrement
i = i + 1;
i += 1;
i++;
++i;
i = i -1;
i -= 2;
--i;
i--;

13. Week 3
Exam Confirmation and Accommodation Requests Due Tomorrow

14. Puzzle int i = 5, j = 2, k; j += 3; k = i++ + --j;
After this executes, what are the values in i, j and k?

15. Puzzle int i = 5, j = 2, k; j = i + 3; k = i++ + --j - 1;
After this executes, what are the values in i, j and k?

16. Floating Down A Circular River?!

17. How many times will this execute?1
until num > 0
until num <= 0
Scanner input = new Scanner(
System.in);
int num;
int sum = 0;
do {
num = input.nextInt();
sum += num;
} while ( num > 0);

18. Body of While will execute...
boolean finished = false;
while ( !finished) {
String line = input.nextLine();
if ( line.equals("done")) {
finished = true;
} else {
System.out.println("echo:" + line); }
until "done" is input
never
forever
other?

19. How many "hello"? for ( int a = 0; a <= 5; a++) {
System.out.print("hello "); } 4 5 6
other?

20. How many "hello"? for ( int a = 5; a >= 1; a++) {
System.out.print("hello "); } 4 5 6
other?

21. How many "bye"? for ( int i = 1; i <= 5; i++) {
for ( int j = 2; j < 6; j++) {
System.out.print("bye "); } 5 9 20
other?

22. What does this print? for ( int i = 1; i <= 5; i++) {
1,1 1,2 1,3
2,1 2,2 2,3
3,1 3,2 3,3
4,1 4,2 4,3
5,1 5,2 5,3
1,1 2,1 3,1
1,2 2,2 3,2
1,3 2,3 3,3
1,4 2,4 3,4
1,5 2,5 3,5
for ( int i = 1; i <= 5; i++) {
for ( int j = 1; j <= 3; j++) {
System.out.print(i+","+j+" "); }
System.out.println();

23. What is the value of count?3 9 12
other
int count = 0;
for ( int i = 1; i < 4; i++) {
for ( int j = 6; j > 3; j--) {
count += 1; }
System.out.println("count=" + count);

24. What is the value of sum? 3 9 12 other int sum= 0;
boolean done = false;
for ( int i = 1; i < 4 && !done; i++) {
for ( int j = 6; j > 3; j--) {
if ( j > 4) continue;
sum += 1; }
if ( i == 3) break;
System.out.println("sum=" + sum); 3 9 12
other