CSE110 Lecture 12

Principles of Programming with Java
Loops: while and do/while statements
(202005)

Transcript

1. CSE110 Principles of Programming with Java Lecture 12: Loops: while and do/while statements 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. while Statement
4. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 4 The while Statement • The while statement has the following syntax:
5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5 Logic of a while Loop zero or more
6. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6 Example 1
7. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 7 The while Statement • Note that if the condition of a while statement is false initially, the statement is never executed • Therefore, the body of a while loop will execute zero or more times
8. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 8 Infinite Loops • The body of a while loop eventually must make the condition false • If not, it is an infinite loop, which will execute until the user interrupts the program
9. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 9 Example 2
10. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 10 Nested Loops • Similar to nested if statements, loops can be nested as well. That is, the body of a loop can contain another loop • Each time through the outer loop, the inner loop goes through its full set of iterations
11. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 11 Example 3
12. do-while Statement
13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13 The do-while Statement • The do-while statement has the following syntax:
14. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 14 Logic of a do-while Loop one or more
15. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 15 Example 4
16. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 16 The do-while Statement • A do loop is similar to a while loop, except that the condition is evaluated after the body of the loop is executed • Therefore the body of a do loop will execute at least once
17. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 17 Example 5
18. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 18 Comparing while and do-while
19. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 19 Test yourselves ?
20. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 20 Reference Chapter 4
21. 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.