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Midterm 2 review Pseudocode: Flowchart Fixing non functioning lamp algorithm 5/23/2017 2 Data types • Three categories of primitive data types: numerical, string, and boolean. • A numerical variable represents a number. • A string variable represents text, for example "2" and "asdf". • A boolean represents either true or false. Big O notation ranking Big-O Name Speed Computations O(1) Constant runtime Very fast, does not depend on size of input. Very few, does not depend on size of input O(log(n)) Logarithmic runtime Very fast. Few, depends only a little bit on size of input O(n) Linear runtime Fast. Some, depending linearly on size of input O(n*log(n)) n*log(n) runtime Acceptable. Depends more on size of input O(n2) Quadratic runtime Slow. A lot, depending on size of input. If n doubles, runtime quadruples. O(n3), O(n4), ... Polynomial runtime Very slow. Way too many computations, not very scalable. O(2n) Exponential runtime Intractable (worst). Ridiculous amount of computations, cannot scale. Static vs. Dynamic web page • A static web page is a web page that is delivered to the user exactly as stored. • Dynamic web pages are generated by a web application. Page Structure • HTML elements control the details of how a page gets displayed. • Every HTML document has the following basic structure: <HTML> <HEAD> … </HEAD> <BODY> … </BODY> </HTML> Table Why CSS? • CSS removes the presentation attributes from the structure allowing reusability, ease of maintainability, and an interchangeable presentation layer. • HTML was never meant to be a presentation language. Proprietary vendors have created tags to add presentation to structure. • <font> • <b> • <i> • CSS allows us to make global and instantaneous changes easily. WHAT IS JAVASCRIPT? • JavaScript was designed to add interactivity to HTML pages • JavaScript is a scripting language (a scripting language is a lightweight programming language) • A JavaScript consists of lines of executable computer code • A JavaScript is usually embedded directly into HTML pages • JavaScript is an interpreted language (means that scripts execute without preliminary compilation) • Everyone can use JavaScript without purchasing a license 5/23/2017 9
