csc115 introduction to computer programming
DESCRIPTION
CSC115 Introduction to Computer Programming. Zhen Jiang Dept. of Computer Science West Chester University West Chester, PA 19383 [email protected]. Table of Contents. Structure Selection (Decision) Loop Function Interesting features Graphics Other tools. Selection (Decision). - PowerPoint PPT PresentationTRANSCRIPT
CSC115 Introduction to Computer Programming
Zhen JiangDept. of Computer Science
West Chester UniversityWest Chester, PA 19383
Table of Contents Structure
Selection (Decision) Loop Array and Function
Price is right. Sample execution (click on this link to
try)
Selection (Decision)
ConditionYes
Action 1 Action 2
No
Action 3
Boolean Expression
Yes
Action 1If controlled
Action 2else controlled
No
Action 3
04/22/23 5
If block if condition then
action 1 (statements 1) elseaction 2 (statements 2) end if
action 3 (statement 3)
Legal age to have driver’s license
Condition Simple condition
Format <Value> <relational operators> <Value>
Number value relational operators =, <>, <, >, <=, >=
String value relational operators=, <>
Complex condition And, or, not Truth table, table 4, p121
Relational operators have lower precedence than math operators.
(7 - 1) * 5 + 3 > 7* 5 6 * 5 + 3 > 35 30 + 3 > 35
33 > 35 False
Relational operators cannot be chained (unlike math operators)
2 <= x <= 10error!
04/22/23 9
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!
Development Process
Multiple selection Nested if block Example: letter grade
Comments: Nested if block for multiple section
problemIf then
case 1Else
if thencase 2else…end if
End if
If block, extension without else if condition then
action 1 (statements 1)
end if action 3 (statement 3)
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x >10 then
y = 2else
y = 3End ifEnd ifListbox1.Items.Add( y )
Are they different, how much?
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x > 10 then
y = 2End ifelse
y = 3End ifListbox1.Items.Add( y )
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x >10 then
y = 2else
y = 3End if
End ifListbox1.Items.Add( y )
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x > 10 then
y = 2End if
elsey = 3
End ifListbox1.Items.Add( y )
Try 0, 4, 11 and see the results!
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x <10 then
y = 2else
y = 3End if
End ifListbox1.Items.Add( y )
Dim x as integer, y as integerx = text1.texty=0if x > 3 then
y =1if x < 10 then
y = 2End if
elsey = 3
End ifListbox1.Items.Add( y )
Try 0, 4, 11 and see a worse situation!
My point One line in wrong place
Could create the program 99.99% different Structural procedure
Ask yourself where (the next program segment line) the computer execution goes
Before that, ask yourself if you can find the “if” for each “else”
Ex 6
Select block Select case
A constant A variable An expression Is To range Else And and or
Loop Do while Loop
do while conditionstatements
loop statements2
Yes
statements1 Action 2
No
Action 3
condition
Yes
Statements1
No
Statements2
condition
Other loops
Clock
Function and procedure
Array