Working with comparison operators

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Working with comparison operators

  1. 1. Working with Comparison OperatorsJesselle CapaCharles Justine Bool
  2. 2. Comparison OperatorsOperators that compare data values to produce true or false results. ASCII Contains a list of characters with corresponding unique numeric representation
  3. 3. Comparison OperatorsOperator Usage Description > lblSales.Caption > The greater than operator return True Only Goal if the value on the right. < Pay < 2000.0 The less than operator return True if the value on the left of < is less than the value on the right. = Age = Limit The equal to operator return True if the value on the both sides of = are equal. >= FirstName >= The greater than or equal to operator “Mike” return True if the value on the left of >= is greater than or equal to the value on the right. <= Num <= The less than or equal to operator return lblAmt.Caption True if the value on the left of <= is less than or equal to the value on the right. <> txtAns.text<> The not equal to operator return True if the “Yes” value on the left of <> is unequal to the value on the right.
  4. 4. Relationship Results Relation Result 2>1 True 3<3 False 5 > 10 True “Apple” <= “Orange” True“Macdonald “ < “Mc Donald” True 0 >=0 True 0 <=0 True 1 <>2 True 2 >=3 False
  5. 5. Working with If Statement The If statement provides logic for the application, w/c analyzes data and makes decisions based on the analysis. The If statement uses comparison operators to test data values and performs one of two possible actions based on the results of the comparison‟s test. Without the If statement, the application code will sequentially execute . Meaning , one statement is executed after another.
  6. 6. The If statement is usuallywritten in the followingformat: If comparisonTest Then One or more statements End If
  7. 7. If Statement and Comparison Keep in mind that the body of the If statement executes based on the results of the comparison test. The statement executes if the results is true. Otherwise , the rest of the application executes as usual and the If statement will be skipped. Data that are entered into a text box control is treated as a Variant data type . When arithmetic is performed with a Variant with data type that holds a numeric value . Visual Basic will convert such data to a number for the calculation purposes.
  8. 8. The If statements Else Branching The If statement with Else is usually written in the following format: If comparisontest Then one or more statements Else one or more statements End If
  9. 9. Compound Comparison with the Logical OperatorsOperator Usage Description And If (A > B) And (C < Returns True if both sides D) of the And are true. Or If (A > B) Or (C < Returns True if either side D) of the Or is true. Not If Not (strAns = Returns the opposite true “Yes”) or false result.
  10. 10. Example :Private Sub cmdGetStudentGrade_Click()„Code for Generating Students Grade„Declare VariablesDim percent As Integer, studentmark As String„Clear text Box txtGrade.Text = ""„Get Students Mark from inputbox percent = InputBox("Enter Students Percent")
  11. 11. Begin if statement If percent >= 50 And percent < 60 Then studentmark = "C" Else percent >= 60 And percent < 70 Then studentmark = "B" Else percent >= 70 Then studentmark = "A" Else studentmark = "FAIL" End IfDisplay Output txtGrade.Text = studentmarkEnd Sub
  12. 12. Nesting If-Else StatementsIf (intAge = 5) Then lblTitle.Caption = “Kindergarten”Else If (intAge = 6) Then lblTitle.Caption = “1st Grade” Else If (intAge = 7) Then lblTitle.Caption = “2nd Grade”
  13. 13. If (intAge = 8) Then lblTitle.Caption = “3rd Grade”Else If (intAge = 9) Then lblTitle.Caption = “4th Grade” Else If (intAge = 10) Then lblTitle.Caption = “5th Grade” Else If (intAge = 11) Then lblTitle.Caption = “6th Grade” Else
  14. 14. lblTitle.Caption = "Advanced" End If End If End If End If End If End IfEnd If
  15. 15. Using Select Case Statement The Select Case Statement handles multiple – choice conditions better than If-Else . When several choices are possible , programmers usually use Select Case as a substitute for long , nested If-Else , but you may find out that it is easier to code and to maintain . However , you must avoid using the Select Case if you will have a simple If or If- Else for the code , unless you need to compare against more than two values . Otherwise , stick with the simple If and If- Else statements
  16. 16. Select Case intAge Case 5 : lblTitle.Caption = "Kindergarten" Case 6 : lblTitle.Caption = "1st Grade" Case 7 : lblTitle.Caption = "2nd Grade" Case 8 : lblTitle.Caption = "3rd Grade" Case 9 : lblTitle.Caption = "4th Grade" Case 10 : lblTitle.Caption = "5th Grade Case 11 : lblTitle.Caption = "6th Grade Case Else : lblTitle.Caption = "Advanced"End Select
  17. 17. 3 Select Case Optional Formats: Select Case Expressions Case Is Relation : One or more Statements Case Is Relation : One or more Statements [Case Is Relation : One or more Statements] [Case Is Relation : One or more Statements] End Else
  18. 18. Select Case Expressions Case Value One or more Visual Basic Statements Case Value One or more Visual Basic Statements [Case Value One or more Visual Basic Statements] [Case Value One or more Visual Basic Statements]End Else
  19. 19. Select Case Expressions Case expr1 To expr2 : One or more Visual Basic Statements Case expr1 To expr2 : One or more Visual Basic Statements [Case expr1 To expr2 : One or more Visual Basic Statements] [Case Else : One or more Visual Basic Statements]End Else

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