CSCI S-1Section 3

Deadlines for Homework 2

• Problems 1-8 in Parts C and D– Friday, July 3, 17:00 EST

• Parts E and F– Tuesday, July 7, 17:00 EST

Connecting to your FAS account (nice.fas.harvard.edu)

• Mac OS: Terminal– http://isites.harvard.edu/fs/docs/icb.topic576155.files/terminal.pdf

• Windows: SecureCRT– http://isites.harvard.edu/fs/docs/icb.topic576155.files/securecrt.pdf

• Downloads site– http://www.fas-it/fas.harvard.edu/

Getting around in Linuxhttp://isites.harvard.edu/fs/docs/icb.topic576155.files/UNIX_commands_reference_card.pdf

• Listing files• Changing directories• Making directories• Removing directories• Removing files• Copying files• Moving files• Print file to monitor• Your present working

directory

• ls• cd• mkdir• rmdir• rm• cp• mv• cat• pwd

Using Nano

• To edit a textfile– nano filename

• Inside nano– control+O to save– control+X to exit– additional commands explained in the help at the

bottom of the screen.

Submitting Homework• Setup your account by running ~libs1/pub/bin/s1setup• Execute the logout command by typing logout and then enter• Login again and make a directory to hold all of your homework

– mkdir s1

• Get into s1– cd s1

• Make a directory for parts C, D (ps21) and E, F (ps22)– mkdir ps21– mkdir ps22

• Test-drive the submit tool by submitting a temporary part 1– s1submit ps21

• NB: Your last submission is the one timestamped and graded.

Java ExercisesType up this simple program in nano and save it as section3.java

class section3{ public static void main(String [] args) { System.out.println("Hello!"); }}

Compile it: javac section3.java

Run it: java section3

Java ExercisesWrite a java program that will print the following

H E L L O \ \ _ " ."JAVAProgramming

class section3a{ public static void main(String [] args) { System.out.println("H E L L O\\\\_ \" .\""); System.out.println("JAVA"); System.out.println("Programming"); }}

Java ExercisesRewrite the program using one method to print each line

class section3b{ static void firstLine() { System.out.println("H E L L O\\\\_ \" .\""); } static void secondLine() { System.out.println("JAVA"); } …

public static void main(String [] args) { firstLine(); secondLine(); thirdLine(); }}

Understanding Variable Scopeclass section3c { static int x, y, z; static void first() { int x, y; x = 0; y = 1; System.out.println("x = " + x + " , y = " + y + " z = " + z); } static void second() { int z; y = 7; z = 1; System.out.println("x = " + x + " , y = " + y + " z = " + z); } static void third() { int y; x = 7; y = 1; System.out.println("x = " + x + " , y = " + y + " z = " + z); } public static void main(String [] args) { x = 2; y = 2; z = 3; first(); second(); third(); }}

Understanding Variable Scope (cont)class section3c {… public static void main(String [] args) { x = 2; y = 2; z = 3; System.out.println("x = " + x + " , y = " + y + " z = " + z); first(); second(); third(); System.out.println("x = " + x + " , y = " + y + " z = " + z); }}

x = 2 , y = 2 z = 3x = 0 , y = 1 z = 3x = 2 , y = 7 z = 1x = 7 , y = 1 z = 3x = 7 , y = 7 z = 3