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CSE110 Lecture 13

CSE110 Lecture 13

Principles of Programming with Java
Loops: for statement
(202005)

B546a9b97d993392e4b22b74b99b91fe?s=128

Javier Gonzalez

June 06, 2017
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  1. CSE110 Principles of Programming with Java Lecture 13: Loops: for

    statement Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com Office Hours: By appointment
  2. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 2 Topics

    class global variables methods statements instructions local variables conditional Statements if-else switch ?: loop Statement while do-while for
  3. for Statement

  4. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 4 The

    for Statement The for statement has the following syntax:
  5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5 The

    for Statement • A for loop is functionally equivalent to the following while loop structure: //initialization while ( condition ) { // statement // increment or update }
  6. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6 Example

    1
  7. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 7 Logic

    of a for loop
  8. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 8 The

    for Statement • Like a while loop, the condition of a for statement is tested prior to executing the loop body • Therefore, the body of a for loop will execute zero or more times • It is well suited for executing a loop a specific number of times that can be determined in advance
  9. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 9 The

    for Statement Each expression in the header of a for loop is optional: • If the initialization is left out, no initialization is performed • If the condition is left out, it is always considered to be true, and therefore creates an infinite loop • If the increment is left out, no increment operation is performed Both semi-colons are always required in the for-loop header.
  10. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 10 Example

    1
  11. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 11 Example

    2
  12. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 12 Example

    3
  13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13 Example

    4 for ( ; ; ) { System.out.println(”I am here! "); }
  14. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 14 Choosing

    a Loop Structure • When you can’t determine how many times you want to execute the loop body, use a while statement or a do statement • If it might be zero or more times, use a while statement • If it will be at least once, use a do statement • If you can determine how many times you want to execute the loop body, use a for statement
  15. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 15 Nested

    loops • We can have a loop inside of another loop for (int i=1; i<=3; i=i+1) { for (int j=4; j>=1; j=j-1) { System.out.println( i + "," + j ); } }
  16. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 16 One

    more thing • variable = variable + 1; variable++; • variable = variable - 1; variable--;
  17. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 17 One

    more thing • We can have a loop inside of another loop for (int i=1; i<=3; i++) { for (int j=4; j>=1; j--) { System.out.println( i + "," + j ); } }
  18. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 18 Reference

    Chapter 4
  19. CSE110 - Principles of Programming Javier Gonzalez-Sanchez javiergs@asu.edu Summer 2020

    Disclaimer. These slides can only be used as study material for the class CSE110 at ASU. They cannot be distributed or used for another purpose.