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Published byBartholomew Horton Modified over 8 years ago
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Fourth Quarter
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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.
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Body of the Loop : Set of statements which is repeated. Loop Exit Condition: condition to be tested before each repetition.
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Start : the starting or the beginning point of the loop. One may start with first or the last record in the file.
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Step : the manner on how the records are to be processed in the given file. Proper sequencing is needed (ascending or descending).
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Stop : the ending point. It is normally represented in a form of a conditional expression, thus, a decision symbol is used in the flowchart
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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
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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?
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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?
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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
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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
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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
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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.
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For = to Step Next
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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
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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
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For = to Step Next
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Dim counter as integer Lbloutput.text = “” For counter = 10 to 1 step -1 lbloutput.text = lbloutput.text & chr(13) & counter Next
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Dim counter as integer Lbloutput.text = “” For counter = 9 to 1 step -2 lbloutput.text = lbloutput.text & chr(13) & counter Next
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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
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Do while Loop
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Private Sub Command1_Click( ) Dim N As Integer N = 0 Do While N < 10 N = N + 1 Print N Loop End Sub
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Private Sub Command1_Click( ) Dim N As Integer N = 0 Do While N < 10 N = N + 1 Print N Loop End Sub Loop Statement
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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
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Do Loop while
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Private Sub Command1_Click( ) Dim N As Integer N = 0 Do N = N + 1 Print N Loop While N < 10 End Sub
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Test condition also appears at the TOP of the LOOP. Executes the block of statements as long as the test condition is FALSE
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Do until Loop
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Private Sub Command1_Click( ) Dim N As Integer N = 0 Do Until N >= 10 N = N + 1 Print N Loop End Sub
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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.
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Hands – On Session
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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.
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Filenames: ◦ Activity No.1 4Act12CN ◦ Activity No.2 4Act22CN
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