Problem Solving Techniques - Computer Fundamentals - Lecture Slides, Slides of Computer Science

Download Problem Solving Techniques - Computer Fundamentals - Lecture Slides and more Slides Computer Science in PDF only on Docsity! Contents • Today's Topic: Problem Solving Techniques • We will learn 1. Problem Statement. 2. Algorithm  Types, Example 3. Flowchart  Symbols, Examples. Docsity.com Problem Solving Techniques Docsity.com Algorithm (Contd…): • To find largest of three numbers 1) Start 2) Read 3 numbers: num1, num2, num3 3) if num1 > num2 then go to step 5 4) if num2 > num3 then print num2 is largest else print num3 is largest goto step 6 5) if num1 > num3 then print num1 is largest else print num3 is largest 6) end. Docsity.com Algorithm (Contd…): Example: One of the simplest algorithms is to find the largest number in an (unsorted) list of numbers. High-level description: 1) Assume the first item is largest. 2) Look at each of the remaining items in the list and if it is larger than the largest item so far, make a note of it. 3) The last noted item is the largest in the list when the process is complete. Docsity.com Algorithm (Contd…): Formal description: Written in prose but much closer to the high-level language of a computer program, the following is the more formal coding of the algorithm in pseudo code (find the largest number in an (unsorted) list of numbers) Algorithm LargestNumber Input: A non-empty list of numbers L. Output: The largest number in the list L. 1) largest ← L0 for each item in the list L, do 2) if the item > largest, then 3) largest ← the item 4) return largest Docsity.com Flowchart (Contd…): A set of useful standard Flowchart symbols: • Rounded box use it to represent an event which occurs automatically. • Rectangle or box use it to represent an event which is controlled within the process. Typically this will be a step or action which is taken. • Diamond use it to represent a decision point in the process. • Circle use it to represent a point at which the flowchart connects with another process. Docsity.com ADVANTAGES OF USING FLOWCHARTS: • Communication: Flowcharts are better way of communicating the logic of a system • Effective analysis: Problem can be analyzed in more effective way. • Proper documentation: Flowcharts serve as a good program documentation • Efficient Coding: Flowcharts act as a guide or blueprint during the systems analysis and program development phase. Docsity.com ADVANTAGES OF USING FLOWCHARTS (Contd…): • Proper Debugging: Flowchart helps in debugging process. • Efficient Program Maintenance: The maintenance of operating program becomes easy with the help of flowchart. Docsity.com The flow chart of the if statement: Body of if Docsity.com The flow chart of the if...else statement: Test expression True Body of if Body of else Docsity.com The flow chart of the switch statement: switch variable equals first case constant First case body switch variable equals second case constant Second case body switch variable equals third case constant Third case body Default body ae ® Docsity.com Start Read A, B Is A > B Print A Print B End Yes No Flow Chart to find largest of two numbers: Docsity.com Flowchart to find the largest of three numbers A,B, and C: NO Docsity.com LIMITATIONS OF USING FLOWCHARTS: • Complex logic: Sometimes, the program logic is quite complicated. In that case, flowchart becomes complex and clumsy. • Alterations and Modifications: If alterations are required the flowchart may require re-drawing completely. • Reproduction: As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem. Docsity.com