1. Sequence, Selection, Iteration The IF Statement
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Sequence, Selection, Iteration
The IF Statement

2. IF Statement Simplified basic syntax: IF condition statement
What is a condition?
An expression formed using relational or logical operators

3. Relational Operators = equal to > greater than < less than
NOT = not equal to
NOT > not greater than
NOT < not less than
>= greater than or equal to
<= less than or equal to

4. Logical Operators AND OR
Compound Conditions – conditional expressions formed by usage of one or more logical operators, for example,
IF A < 100 AND B >
IF A = 0 OR B =
IF A > 0 AND B > 0 OR C <

5. Precedence for Evaluation of Logical Expressions
HIGH simple condition (relational expression) complex condition in parentheses NOT AND
LOW OR
Consider: NOT (NOT A < 10 AND B = 4) {if A=6, B=6}

6. Precedence for Evaluation of Logical Expressions
HIGH simple condition complex condition in parentheses NOT AND
LOW OR
Consider: NOT (NOT A < 10 AND B = 4) {if A=6, B=6}
T F

7. Precedence for Evaluation of Logical Expressions
HIGH simple condition complex condition in parentheses NOT AND
LOW OR
Consider: NOT (NOT A < 10 AND B = 4) {if A=6, B=6}
T F
false

8. Precedence for Evaluation of Logical Expressions
HIGH simple condition complex condition in parentheses NOT AND
LOW OR
Consider: NOT (NOT A < 10 AND B = 4) {if A=6, B=6}
T F
false

9. Precedence for Evaluation of Logical Expressions
HIGH simple condition complex condition in parentheses NOT AND
LOW OR
Consider: NOT (NOT A < 10 AND B = 4) {if A=6, B=6}
T F
false
true

10. Logical Expressions (Conditions)
Can appear in clauses other than IF statement.
PERFORM …UNTIL
EVALUATE
other . . .

11. IF with ELSE Simplified basic syntax:
IF condition statement(s) ELSE statement(s)
END-IF