CSC1100 - Chapter12 - Flow Charts
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Here is a flowchart to calculate bonus for an employee based on their annual hours worked: Start Declare variables: AnnualHours, Bonus Get AnnualHours AnnualHours < 2000 True Bonus = RM500 False AnnualHours >= 2000 and <= 2499 True Bonus = RM500 + 1 month salary False Bonus = RM500 + 2 months salary Display Bonus Stop
CSC1100 - Chapter12 - Flow Charts
- 2. 2 Problem Solving Can be solved in a series of actions Problem solving steps: 1. Identify the problem 2. Understand the problem 3. Identify alternatives (solutions) 4. Select the best solution4. Select the best solution 5. Prepare a list of steps (instruction) 6. Evaluate the solution
- 3. 3 SOLUTIONS Algorithmic Heuristic the best alternative solution reached by completing actions in steps – algorithm cannot be reached through direct set of steps – require reasoning built on knowledge & experience – a process of trial & error
- 4. 4 Problem Solving with Computers Solution instructions listed during step 5 of problem solving – must be followed to produce best results Result The outcome or completed computer-assisted answer Program Computers deal with algorithmic solutions & heuristic solutions (artificial intelligence) Program set of instructions that make up the solution after they have been coded into a particular computer language
- 5. 5 Constants & Variables Constant An alphabetical and/or numerical value that never changes during the processing of all the instructions in a solution Variable (identifiers) May change during processing Given a name & a location in memory - Referred to by given name
- 6. 6 Drawing the Flowcharts Connect blocks by exiting from one and entering another The arrowhead is necessary FLOWLINESFLOWLINES Indicate the start & end of a program StartStart has one flowline exiting ExitExit has one flowline entering StartStart ExitExit
- 7. 7 Drawing the Flowcharts (cont.) For calculations,… Has one flowline entering and one exiting PROCESSINGPROCESSING Indicates input to and output from the computer memory Has one entrance & one exit I/OI/O
- 8. 8 Drawing the Flowcharts (cont.) Indicates a decision Has one entrance & two exits One exit is the action when the resultant is TRUE & other exit is the action when the resultant is FALSEDecisionDecision i < 10 T F Display “i is less than 10” ExitExit
- 9. 9 Problem Solving with Computers Problem: Display Area of a Circle Steps to solve the problem: 1. Declare & Initialize PI value 2. Declare & Initialize Radius value 3. Declare & Initialize Area value 4. Calculate Area 5. Display the value of Area
- 10. 10 Drawing the Flowchart & Writing Algorithm Display Area of a Circle Start Declare & initialize PI, Radius and Area Algorithm 1. Constant PI = 3.142 2. Variable Radius = 10 Exit Calculate Area Display Area 2. Variable Radius = 10 3. Variable Area = 0.0 4. Area = PI x Radius x Radius 5. Display Area
- 11. 11 Writing the Algorithms Display Area of a Circle Algorithm 1. Constant PI = 3.142 2. Variable Radius = 10 3. Variable Area = 0.0 4. Area = PI x Radius x Radius 5. Display Area … PI = 3.142 … …5. Display Area … Radius = 40 … Area = 0.0 … 314.2314.2 Output at monitor screen
- 12. 12 Drawing the Flowchart & Writing Algorithm Display Area of a Circle Start Declare & initialize PI, Radius and Area Algorithm 1. Declare Constant PI=3.142, 2. Variable Radius=0 Get Radius Exit Calculate Area Display Area 2. Variable Radius=0 3. Variable Area=0.0 4. Get Radius 5. Area = PI x Radius x Radius 6. Display Area
- 13. 13 PROGRAM STRUCTUREPROGRAM STRUCTUREPROGRAM STRUCTUREPROGRAM STRUCTURE
- 14. 14 Program Structure Use FOUR logic structures to ensure the solution flows smoothly from one instruction to the next, rather than jumping between points 1. Sequential structure executes instructions one after another in a sequence 2. Decision structure branches to execute one of the possible sets of instructionsinstructions 3. Loop structure executes a set of instructions many times 4. Case structure executes a set of instructions out of several sets Efficient by providing smooth transformation of data into information besides eliminating the rewriting of identical processes Techniques to improve program readability: the 4 logic structure, proper naming of variables, internal documentation and proper indentation
- 15. 15 Figure 1: Sequential Logic Structure
- 16. 16 Figure 2: Decision Logic Structure
- 17. 17 Figure 3: Loop Logic Structure
- 18. 18 Figure 4: Case Logic Structure
- 19. 19 Problem Solving with Computers (e.g.)
- 20. 20 Draw a flowchart to calculate bonus for an employee based on the following table: Annual Hours Worked Bonus Less than 2000 hours RM 500Less than 2000 hours RM 500 Between 2000 and 2499 hours RM 500 + 1 month salary More than 2500 hours RM500 + 2 months salary