topic 2.3 revision

topic 2.3 revision

1. sequence, selection and iteration

   • sequence- when lines of code are executed one after the other in a logical manner.
   • selection- when a decision has to be made during a section of code. The most common example is an "if statement"
   • iteration- when a section of code of repeated. E.g DO and FOR loops

2. Data types

   • integer-whole numbers e.g 12, 0, -25
   • float/real-numbers with decimal place e.g 0.42, 1.00, -456.786
   • string-word or phrase e.g "Hello"
   • character- letters, numbers or punctuation e.g 'a', '78', '?'
   • boolean- 'true' or 'false'

3. Arrays

   • An array is a data structure. it is used to hold lots of different items belonging to the same data type.

4. defensive design considerations

   • input validation- this is an automatic computer check to ensure that the data entered is sensible and reasonable.
     • input sanitation- this modifies the input to ensure that it is valid