COMP 110 Even more loops and stuff

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COMP 110Even more loops and stuff

• Luv Kohli
• September 17, 2008
• MWF 2-250 pm
• Sitterson 014

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Announcements

• Microsoft info session tomorrow night,
  530pm-630pm, SN014
• Free food, bring résumé for chance to win prizes
• Lab 3 due Friday, 2pm
• Remember to print out your modifyFace() method
  and hand it in

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Policy and such

• YOU are responsible for making sure assignments
  are turned in correctly
• Read each assignment EARLY and COMPLETELY
• Start EARLY and ask questions EARLY if something
  doesnt make sense
• Come to office hours
• When I ask in-class questions, raise your hand

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Questions?
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Today in COMP 110

• Go over Lab 2
• More about loops

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Lab 2

• Convert to uppercase letters
• toUpperCase() method
• Print characters at positions 0 and 5
• charAt() method
• Substring starting at 0 and ending at 5
• substring() method
• Without first word
• indexOf() and substring() methods

W h a t i s y o u r n a m e ?
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Lab 2

• Convert to uppercase letters
• JOptionPane.showMessageDialog(null,
  inputString.toUpperCase())

W H A T I S Y O U R N A M E ?
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Lab 2

• Print characters at positions 0 and 5
• JOptionPane.showMessageDialog(null,inputString.ch
  arAt(0) ", " inputString.charAt(5))

W h a t i s y o u r n a m e ?
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Lab 2

• Substring starting at 0 and ending at 5
• JOptionPane.showMessageDialog(null,
  inputString.substring(0, 6))

W h a t i s y o u r n a m e ?
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Lab 2

• Without first word
• JOptionPane.showMessageDialog(null,inputString.su
  bstring(inputString.indexOf( ) 1))

W h a t i s y o u r n a m e ?
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Review Types of Loops

• while
• Safest choice
• Not always most elegant
• do-while
• Loop iterates AT LEAST once
• for
• Similar to while, but often more convenient syntax

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Review Using a while loop

• int n 1
• while (n lt 10)
• System.out.println(n)
• n n 1

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Review Using a do-while loop

• int n 1
• do
• System.out.println(n)
• n n 1
• while (n lt 10)

Dont forget the semicolon!
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Review Using a for loop

• int n
• for (n 1 n lt 10 n)
• System.out.println(n)

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for loop and the comma operator

• Used to perform more than one initializing action
  or more than one update action
• int n
• int product
• for (n 1, product 1 n lt 5 n)
• product product n
• System.out.println(product)

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The break statement

• Where have we seen break before?

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The break statement

• Causes the immediately enclosing switch statement
  or loop to end the remainder of the loop (or
  switch) is not executed
• Why might you want a loop to end early?

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The break statement

• Example You can buy up to 5 items, but you have
  a budget of 100. Buy items until you have
  exceeded your budget.

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The break statement

• for (int item 1 item lt 5 item)
• System.out.print(Enter cost of item
  item )
• amount keyboard.nextDouble()
• total total amount
• if (total gt 100)
• System.out.println(You spent all your
  money.)
• break
• System.out.println(Your total so far is
  total)
• System.out.println(You spent total)

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Friday

• Lab 3 due, 2pm

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