CSC115 Introduction to Computer Programming

1
CSC115 Introduction to Computer Programming

• Zhen Jiang
• Dept. of Computer Science
• West Chester University
• West Chester, PA 19383
• zjiang_at_wcupa.edu

2
Table of Contents

• Structure
• Selection (Decision)
• Loop
• Array and Function

3
Selection (Decision)

• Price is right.
• Sample execution (click on this link to try)

4
No
Yes
Condition
Action 1
Action 2
Action 3
5
Yes
No
Boolean Expression
Action 1 If controlled
Action 2 else controlled
Action 3
6

• If block
• if condition then
• action 1 (statements 1)
• else
• action 2 (statements 2)
• end if
• action 3 (statement 3)

7

• Legal age to have drivers license

?
8

• Legal age to have drivers license

9

• Condition
• Simple condition
• Format
• ltValuegt ltrelational operatorsgt ltValuegt
• Number value relational operators
• , ltgt, lt, gt, lt, gt
• String value relational operators
• , ltgt
• Complex condition
• And, or, not
• Truth table, table 4, p121

10

• Relational operators have lower precedence than
  math operators.
• 5 7 gt 3 5 (7 - 1)?
• 5 7 gt 3 5 6
• 35 gt 3 30
• 35 gt 33
• true
• Relational operators cannot be chained (unlike
  math operators)
• 2 lt x lt 10
• error!

11
Development Process

• Identify two exclusive options
• Implement each handling in different action parts
• Identify the situation (values) for option
  selection
• Make a condition so that all the situation value
  for option part 1 will lead to this condition
  true.
• Verify all the situation value for option part 2
  will lead to this condition false, otherwise,
  revise the above condition!

12
(No Transcript)
13

• Multiple selection
• Nested if block
• Example letter grade

14

• Comments
• Nested if block for multiple section problem
• If then
• case 1
• Else
• if then
• case 2
• else
• end if
• End if

15

• If block, extension without else
• if condition then
• action 1 (statements 1)
• end if
• action 3 (statement 3)

16
Try 2
Dim x as integer, y as integer x
text1.text y0 if x gt 3 then y 1 if x gt10
then y 2 else y 3 End if End
if Listbox1.Items.Add( y )
Dim x as integer, y as integer x
text1.text y0 if x gt 3 then y 1 if x gt 10
then y 2 End if else y 3 End
if Listbox1.Items.Add( y )
17
Dim x as integer, y as integer x
text1.text y0 if x gt 3 then y 1 if x gt10
then y 2 else y 3 End if End
if Listbox1.Items.Add( y )
Dim x as integer, y as integer x
text1.text y0 if x gt 3 then y 1 if x gt 10
then y 2 End if else y 3 End
if Listbox1.Items.Add( y )
18

• Select block
• Select case
• A constant
• A variable
• An expression
• Is
• To range
• Else
• And and or

19
Loop

• Do while Loop
• do while condition
• statements
• loop
• statements2

20
No
Yes
condition
statements1
Action 2
Action 3
21
No
Yes
condition
Statements1
Statements2
22

• Other loops

23

• Clock

24

• Function and procedure

25

• Array