Selection

• Selection is code that follows a different sequence based on what condition is chosen.
• Criteria is the specific rules that are used by the program to recognise if a condition is TRUE or FALSE. The singular form of criteria is criterion.
• IF statements are statements that allow a program to follow a program to follow or ignore a sequence of code depending on a Boolean condition.
• CASE statements are a simple method of providing multiple paths through the code based on a single variable or user input.
• A condition is the criteria that are tested as part of the execution of the code. The condition will result in either a True or False answer when tested.
• Nested IF statements are IF statements with the ability for additional conditions to be checked once earlier conditions have determined a path.
• ELSEIF statements are an alternative to nested IF statements. Each condition is tested in turn. When a condition is TRUE, the code related to that condition is executed and the statement is ended.
• AND Boolean operators are used to create a condition which is made up from more than one criteria. The condition will only be TRUE if all of the individual criteria are TRUE.
• OR Boolean operators are used to create a condition which is made up from more than one criteria. The condition will be TRUE if any of the individual criteria are TRUE.
• NOT Boolean operators are used to create a condition which will be TRUE when the criteria are FALSE.
• Selection provides methods that programmers can use to allow the algorithm to follow different paths through the code depending on the data being used at the time.
• The flowchart symbol for selection is a decision diamond. The selection criteria are included in the symbol. The exit paths should be indicated as TRUE or FALSE.
• Multiple decisions are shown as a series of connected decisions.
• Logical operators are used to provide a range of comparative options.
• Nested IF statements provide the ability for additional conditions to be checked once earlier conditions have determined a path.
• ELSEIF statements are an alternative to nested IF statements. Each condition is tested in turn. When a conditional is TRUE, the code related to that condition is executed and the statement is ended.
• CASE statements provide a simple method of providing multiple paths based on a single variable or user input.
• The ELSE statement (used with IF) and the OTHERWISE statement (used with CASE) provide a default path should none of the conditions be met.
• Boolean operators can be used with IF statements to provide the ability to use complex conditions based on multiple variables or user inputs.