Chapter 2 - Selection

Chapter 2 - Selection

1. Program Constructs

   • Sequence
     • 2 or more statements one after another.
   • Assignment statements
     • When a value is assigned to a variable.

2. Selection statements

   • Used to select which statement will be executed next, depending on a condition
     • Decided by Rational Operators.
       • E.g. IF (expression1) THEN Do these statements ENDIF
   • Rational Operators
     • > | Greater than
     • < | Less than
     • >= | Greater than or equal
     • = (or == in python) Equal to
     • <= | Less than or equal
     • <> (or != in python) | Not equal to

3. CASE Statements

   • E.g. CASE choice of 1:OUTPUT "You have selected option 1" (more statements here) &nbsp;2:OUTPUT "You have selected option 2" (more statements here) 3:OUTPUT "You have selected option 3" (more statements here) ELSE OUTPUT "You must enter 1,2 or 3" &nbsp;ENDCASE
   • Used instead of a nested If statement
     • Useful when there is a choice between several alternatives

4. Boolean Operators

   • AND Operator
     • Used when both statements are true
   • XOR Operator
   • NOT Operator
   • OR Operator