Presentation is loading. Please wait.

Presentation is loading. Please wait.

CMSC 150 LOOPS CS 150: Fri 20 Jan 2012. Representing DNA AGTCCAGTGTCAA.

Published byRalf Wilson Modified over 8 years ago

Similar presentations

Presentation on theme: "CMSC 150 LOOPS CS 150: Fri 20 Jan 2012. Representing DNA AGTCCAGTGTCAA."— Presentation transcript:

1 CMSC 150 LOOPS CS 150: Fri 20 Jan 2012

2 Representing DNA AGTCCAGTGTCAA

3 Start Codon: ATG

4

5 Consider in Java String dna = “AGTCCAGTGTCAA”;

6 Consider in Java String dna = “AGTCCAGTGTCAA”; if ( dna.substring(0,3).equals(“ATG”) )

7 String dna = “AGTCCAGTGTCAA”; if ( dna.substring(0,3).equals(“ATG”) ) if ( dna.substring(1,4).equals(“ATG”) ) Consider in Java

8 String dna = “AGTCCAGTGTCAA”; if ( dna.substring(0,3).equals(“ATG”) ) if ( dna.substring(1,4).equals(“ATG”) ) if ( dna.substring(2,5).equals(“ATG”) ) Consider in Java

9 String dna = “AGTCCAGTGTCAA”; if ( dna.substring(0,3).equals(“ATG”) ) if ( dna.substring(1,4).equals(“ATG”) ) if ( dna.substring(2,5).equals(“ATG”) ) if ( dna.substring(3,6).equals(“ATG”) ) if ( dna.substring(4,7).equals(“ATG”) )... if ( dna.substring(10,12).equals(“ATG”) )

10 Loops

11 Loop Syntax  while ( condition ) { statement ; }  for ( initialization; condition; update ) { statement ; }

12 Loop Syntax  while ( condition ) { statement ; }  for ( initialization; condition; update ) { statement ; } Use while when you don’t know in advance the # of times to loop Use while when you don’t know in advance the # of times to loop

13 Loop Syntax  while ( condition ) { statement ; }  for ( initialization; condition; update ) { statement ; } Use for when you know in advance the # of times to loop Use for when you know in advance the # of times to loop

14 While Loop Syntax  while ( condition ) { statement_to_execute; }  build a condition that eventually becomes false  need statement w/in body to advance toward false  condition evaluated each time before executing statement

15 While Loop Example  while ( condition ) { statement_to_execute; }  int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count); count++; }

16 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0

17 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so…

18 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0

19 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1

20 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so…

21 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1

22 While Loop Action int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1 7. execute statement: increment count to 2

23 int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } While Loop Action 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1 7. execute statement: increment count to 2 8. evaluate condition: count < 3 is true, so…

24 int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } While Loop Action 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1 7. execute statement: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints count = 2

25 int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } While Loop Action 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1 7. execute statement: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints count = 2 10. execute statement: increment count to 3

26 int count = 0; while ( count < 3 ) { System.out.println( “count = “ + count ); count++; } While Loop Action 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints count = 0 4. execute statement: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints count = 1 7. execute statement: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints count = 2 10. execute statement: increment count to 3 11. evaluate condition: count < 3 is false, so exit the loop

27 For Loop Syntax  for ( initialization; condition; update ) { statement_to_execute; } typically declare and initialize a variable for the loop: int count = 0; executed exactly once, as loop starts

28 For Loop Syntax build a condition based on the loop variable that eventually becomes false count < 3; evaluated each time before executing statement  for ( initialization; condition; update ) { statement_to_execute; }

29 For Loop Syntax statement that advances the condition toward failure count = count + 1 executed each time after executing statement  for ( initialization; condition; update ) { statement_to_execute; }

30 For Loop Example  for ( initialization; condition; update ) { statement_to_execute; }  for ( int count = 0; count < 3; count++ ) { System.out.println( "Count = " + count ); }

31  for ( initialization; condition; update ) { statement_to_execute; }  for ( int count = 0; count < 3; count++ ) { System.out.println( "Count = " + count ); } For Loop Example

32  for ( initialization; condition; update ) { statement_to_execute; }  for ( int count = 0; count < 3; count++ ) { System.out.println( "Count = " + count ); } For Loop Example

33 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 { }

34 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… { }

35 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 { }

36 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 { }

37 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… { }

38 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 { }

39 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 7. update: increment count to 2 { }

40 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 7. update: increment count to 2 8. evaluate condition: count < 3 is true, so… { }

41 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 7. update: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints Count = 2 { }

42 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 7. update: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints Count = 2 10. update: increment count to 3 { }

43 For Loop Action for ( int count = 0; count < 3; count++ ) System.out.println( "Count = " + count ); 1. initialize count to 0 2. evaluate condition: count < 3 is true, so… 3. execute statement: prints Count = 0 4. update: increment count to 1 5. evaluate condition: count < 3 is true, so… 6. execute statement: prints Count = 1 7. update: increment count to 2 8. evaluate condition: count < 3 is true, so… 9. execute statement: prints Count = 2 10. update: increment count to 3 11. evaluate condition: count < 3 is false, so exit the loop { }

44 What happens? for ( int count = 0; count > 3; count++ ) System.out.println( "Count = " + count ); { }

45 What happens? for ( int count = 0; count > 3; count++ ) System.out.println( "Count = " + count ); { }

46 What happens? for ( int count = 0; count < 10; count = count++) System.out.println( "Count = " + count ); { }

47 What happens? for ( int count = 0; count < 10; count = count++) System.out.println( "Count = " + count ); infinite loop!! because count++ returns value of count before incrementing { }

48 What happens? for ( int count = 0; count < 10; ) System.out.println( "Count = " + count ); { }

49 What happens? for ( int count = 0; count < 10; ) System.out.println( "Count = " + count ); { } infinite loop!! no update, so count is always 0

50 What happens? for ( int count = 1; count != 10; count += 2) System.out.println( "Count = " + count ); { }

51 What happens? for ( int count = 1; count != 10; count += 2) System.out.println( "Count = " + count ); { }

52 What happens? for ( int count = 0; count < 10; count += 2); System.out.println( "Bill Maher" ); { }

53 What happens? for ( int count = 0; count < 10; count += 2); System.out.println("Bill Maher" ); { } Prints only once because of this!

54 Equivalent for ( int count = 0; count < 10; count += 2); System.out.println( "Bill Maher" ); { } for ( int count = 0; count < 10; count += 2) ; // do-nothing statement System.out.println( "Bill Maher" ); { }

55 What happens? for ( int count = 0; count < 10; count += 2); System.out.println( "Count = " + count ); { }

56 What happens? for ( int count = 0; count < 10; count += 2); System.out.println( "Count = " + count ); { }

57 Guess the Number

58 Start Codon: ATG

59 While Loop or For Loop? String dna = “ATATGCCTG”; if ( dna.substring(0,3).equals(“ATG”) ) if ( dna.substring(1,4).equals(“ATG”) ) if ( dna.substring(2,5).equals(“ATG”) ) if ( dna.substring(3,6).equals(“ATG”) ) if ( dna.substring(4,7).equals(“ATG”) ) if ( dna.substring(5,8).equals(“ATG”) ) if ( dna.substring(6,9).equals(“ATG”) )

60 String dna = “ATATGCCTG”; if ( dna.substring(0,3).equals(“ATG”) ) if ( dna.substring(1,4).equals(“ATG”) ) if ( dna.substring(2,5).equals(“ATG”) ) if ( dna.substring(3,6).equals(“ATG”) ) if ( dna.substring(4,7).equals(“ATG”) ) if ( dna.substring(5,8).equals(“ATG”) ) if ( dna.substring(6,9).equals(“ATG”) ) While Loop or For Loop?

61 Building A For Loop String dna = “ATATGCCTG”; for ( ???????; ???????; ??????? ) { if ( dna.substring(i,i+3).equals(“ATG”) ) { // do something magical }

62 Building A For Loop String dna = “ATATGCCTG”; for ( ???????; ???????; ??????? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical }

63 String dna = “ATATGCCTG”; for ( ???????; ???????; ??????? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

64 String dna = “ATATGCCTG”; for ( int i = 0; ???????; ??????? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

65 String dna = “ATATGCCTG”; for ( int i = 0; i < 7; ??? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

66 String dna = “ATATGCCTG”; for ( int i = 0; i <= dna.length()-3; ????? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

67 String dna = “ATATGCCTG”; for ( int i = 0; i <= dna.length()-3; ????? ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

68 String dna = “ATATGCCTG”; for ( int i = 0; i <= dna.length()-3; i++ ) { if ( dna.substring(?,?).equals(“ATG”) ) { // do something magical } Building A For Loop

69 String dna = “ATATGCCTG”; for ( int i = 0; i <= dna.length()-3; i++ ) { if ( dna.substring(i,i+3).equals(“ATG”) ) { // do something magical } Building A For Loop

70 if ( dna.substring(0,3).equals(“ATG”) ) … if ( dna.substring(1,4).equals(“ATG”) ) … if ( dna.substring(2,5).equals(“ATG”) ) … if ( dna.substring(3,6).equals(“ATG”) ) … if ( dna.substring(4,7).equals(“ATG”) ) … if ( dna.substring(5,8).equals(“ATG”) ) … if ( dna.substring(6,9).equals(“ATG”) ) … for ( int i = 0; i <= dna.length()-3; i++ ) { if ( dna.substring(i,i+3).equals(“ATG”) ) { // do something magical } Building A For Loop

71 for ( int i = 0; i < 7; i++ ) { if ( dna.substring(i,i+3).equals(“ATG”) ) { // do something magical } Write An Equivalent While Loop

72 Digital Images

73 for ( int row = 0; row < image.getNumRows(); row = row + 1 ) { for ( int col = 0; col < image.getNumCols(); col = col + 1 ) { image.getPixelAt( row, col ).brightenByAmt( 10 ); } 01230123 0 1 2 3

74 Digital Images for ( int row = 0; row < image.getNumRows(); row = row + 1 ) { for ( int col = 0; col < image.getNumCols(); col = col + 1 ) { image.getPixelAt( row, col ).brightenByAmt( 10 ); } 01230123 0 1 2 3 row = 0, col loops through values 0…3 row = 1, col loops through values 0…3 row = 2, col loops through values 0…3 row = 3, col loops through values 0…3

Download ppt "CMSC 150 LOOPS CS 150: Fri 20 Jan 2012. Representing DNA AGTCCAGTGTCAA."

Similar presentations

Repetition Statements Perform the same task repeatedly Allow the computer to do the tedious, boring things.

Repetition Statements Perform the same task repeatedly Allow the computer to do the tedious, boring things.
Loops –Do while Do While Reading for this Lecture, L&L, 5.7.

Loops –Do while Do While Reading for this Lecture, L&L, 5.7.
COMP 14 Introduction to Programming Mr. Joshua Stough February 16, 2005 Monday/Wednesday 11:00-12:15 Peabody Hall 218.

COMP 14 Introduction to Programming Mr. Joshua Stough February 16, 2005 Monday/Wednesday 11:00-12:15 Peabody Hall 218.
The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie COMP 14 Introduction to Programming Adrian Ilie July 6, 2005.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie COMP 14 Introduction to Programming Adrian Ilie July 6, 2005.
Introduction to Computers and Programming Lecture 9: For Loops New York University.

Introduction to Computers and Programming Lecture 9: For Loops New York University.
COMP 14 Introduction to Programming Miguel A. Otaduy May 21, 2004.

COMP 14 Introduction to Programming Miguel A. Otaduy May 21, 2004.
Loops – While Loop Repetition Statements While Reading for this Lecture, L&L, 5.5.

Loops – While Loop Repetition Statements While Reading for this Lecture, L&L, 5.5.
A loop is a repetition control structure. it causes a single statement or block to be executed repeatedly What is a loop?

A loop is a repetition control structure. it causes a single statement or block to be executed repeatedly What is a loop?
1 Parts of a Loop (reminder) Every loop will always contain three main elements: –Priming: initialize your variables. –Testing: test against some known.

1 Parts of a Loop (reminder) Every loop will always contain three main elements: –Priming: initialize your variables. –Testing: test against some known.
Introduction to Computers and Programming for Loops  2000 Prentice Hall, Inc. All rights reserved. Modified for use with this course. Introduction to.

Introduction to Computers and Programming for Loops  2000 Prentice Hall, Inc. All rights reserved. Modified for use with this course. Introduction to.
Repetition Statements repeat block of code until a condition is satisfied also called loops Java supports 3 kinds of loops: while statement – repeats a.

Repetition Statements repeat block of code until a condition is satisfied also called loops Java supports 3 kinds of loops: while statement – repeats a.
©2004 Brooks/Cole Chapter 5 Repetition. Figures ©2004 Brooks/Cole CS 119: Intro to JavaFall 2005 Repetition So far, our programs processed a single set.

©2004 Brooks/Cole Chapter 5 Repetition. Figures ©2004 Brooks/Cole CS 119: Intro to JavaFall 2005 Repetition So far, our programs processed a single set.
Loops – While, Do, For Repetition Statements Introduction to Arrays

Loops – While, Do, For Repetition Statements Introduction to Arrays
Loops –For For Reading for this Lecture, L&L, Part of 5.8.

Loops –For For Reading for this Lecture, L&L, Part of 5.8.
ECE122 L11: For loops and Arrays March 8, 2007 ECE 122 Engineering Problem Solving with Java Lecture 11 For Loops and Arrays.

ECE122 L11: For loops and Arrays March 8, 2007 ECE 122 Engineering Problem Solving with Java Lecture 11 For Loops and Arrays.
University of British Columbia CPSC 111, Intro to Computation 2009W2: Jan-Apr 2010 Tamara Munzner 1 Loops III Lecture 19, Wed Mar 3 2010

University of British Columbia CPSC 111, Intro to Computation 2009W2: Jan-Apr 2010 Tamara Munzner 1 Loops III Lecture 19, Wed Mar
Loops Repetition Statements. Repetition statements allow us to execute a statement multiple times Often they are referred to as loops Like conditional.

Loops Repetition Statements. Repetition statements allow us to execute a statement multiple times Often they are referred to as loops Like conditional.
© 2004 Pearson Addison-Wesley. All rights reserved5-1 Iterations/ Loops The while Statement Other Repetition Statements.

© 2004 Pearson Addison-Wesley. All rights reserved5-1 Iterations/ Loops The while Statement Other Repetition Statements.
Copyright © Texas Education Agency, 20131 Computer Programming For Loops.

Copyright © Texas Education Agency, Computer Programming For Loops.
ECE122 L9: While loops March 1, 2007 ECE 122 Engineering Problem Solving with Java Lecture 9 While Loops.

ECE122 L9: While loops March 1, 2007 ECE 122 Engineering Problem Solving with Java Lecture 9 While Loops.

Similar presentations

Ads by Google