Fourth Quarter

 Involves loops or cycles ◦ Loops: means that a process may be repeated as long as certain condition remains true or remains false. ◦ Means “multiple processing”  Provides means of repeating a part of instruction without rewriting the part again and again.

 Body of the Loop : Set of statements which is repeated.  Loop Exit Condition: condition to be tested before each repetition.

 Start : the starting or the beginning point of the loop.  One may start with first or the last record in the file.

Step : the manner on how the records are to be processed in the given file. Proper sequencing is needed (ascending or descending).

Stop : the ending point. It is normally represented in a form of a conditional expression, thus, a decision symbol is used in the flowchart

 Is a variable that defines the starting, ending point and step of a looping statement.  It should be a variable that will uniquely identify all the records in the file.  It is a representation of a field in the record. The shorter the value, the better is the field

 Draw a flowchart that will read the grades in PT, CS and QS of student. Compute the average of the student. Print the name and the computed average.  Input :  Process:  Output:  Will there be multiple processing? How many times the inputting, processing and outputting will be performed? WHY?

 Draw a flowchart that will read the grades in PT, CS and QS of all the students in the class of II - ____. Compute the average of all the students. Print the names and the computed averages.  Input :  Process:  Output:  Will there be multiple processing? How many times the inputting, processing and outputting will be performed? WHY?

 Are used to literally count the number of times a portion of the flowchart is traced.  Need to be initialized / prepared prior to its use or application.  The operation involved is “addition”  The increment value is a constant  Example: C = C + 1 Increment Value Current Value New Value

 A numerical value that collects the result of a repeated mathematical operation.  Used to keep a running total of an item / the operation involved is “addition”.  Need to be initialized / prepared prior to its use or application.  The incremental value is a “variable” (subjected to change)  Example: S = S + N Increment Value  Current Value New Value

 Executes a group of instructions repeatedly  Has 3 Structures: ◦ For ……. Next ◦ Do …….. Loop : has three types:  Do While …. Loop  Do Until …. Loop  Do …… Loop while ◦ While ….. Wend

 Executes a section of the code a specified number of times.  Begins with the “for” statement and ends with the “next” statement.  Can only be used if the programmer knows the number of times the loop must be performed prior to its execution.

For = to Step Next

Dim UserName as string Dim times as integer Username = “Paul” Lbloutput.text = “ ” For times = 1 to 10 step 1 Lbloutput.text = lbloutput.text & chr(13) & Username Next times

Dim UserName as string Dim times as integer Username = “Paul” Lbloutput.text = “ ” For times = 1 to 10 Lbloutput.text = lbloutput.text & chr(13) & Username Next

For = to Step Next

Dim counter as integer Lbloutput.text = “” For counter = 10 to 1 step -1 lbloutput.text = lbloutput.text & chr(13) & counter Next

Dim counter as integer Lbloutput.text = “” For counter = 9 to 1 step -2 lbloutput.text = lbloutput.text & chr(13) & counter Next

 Most common statement among the do..loop statements  Test condition appears at the TOP of the loop ◦ As long as the test condition is TRUE, the block of code in the body of the loop will be continuously executed ◦ When the test condition becomes FALSE, the loop terminates.  Condition before iteration

Do while Loop

Private Sub Command1_Click( ) Dim N As Integer N = 0 Do While N < 10 N = N + 1 Print N Loop End Sub

Private Sub Command1_Click( ) Dim N As Integer N = 0 Do While N < 10 N = N + 1 Print N Loop End Sub Loop Statement

 The test condition appears at the bottom of the loop.  When the test condition stays TRUE, the loop still executes until it becomes false  Condition after iteration

Do Loop while

Private Sub Command1_Click( ) Dim N As Integer N = 0 Do N = N + 1 Print N Loop While N < 10 End Sub

 Test condition also appears at the TOP of the LOOP.  Executes the block of statements as long as the test condition is FALSE

Do until Loop

Private Sub Command1_Click( ) Dim N As Integer N = 0 Do Until N >= 10 N = N + 1 Print N Loop End Sub

DO WHILE / DO UNTIL Display numbers from 1 to 10  Do While N < 10 N = N + 1 Print N Body of Loop will be executed as long as the condition is TRUE. Display numbers from 1 to 10  Do Until N >= 10 N = N + 1 Print N Body of Loop will be executed as long as the condition is FALSE.

Hands – On Session

a. Make a program that will display this output on the form: b. Make a program that will display “Patience is a Virtue” 5 times.

 Filenames: ◦ Activity No.1  4Act12CN ◦ Activity No.2  4Act22CN