Prof. B. I. Khodanpur HOD – Dept. of CSE R. V. College of Engineering. EmailID: bi.khodanpur@gmail.com

1. Prof. B. I. KhodanpurHOD – Dept. of CSER. V. College of Engineering.EmailID:bi.khodanpur@gmail.com Subject: Computer Fundamentals (For EDUSAT) Common Paper for BA / B.Com / B.Sc Code: CS-54

2. Types of OS: Operating System can also be classified as,- • Single User Systems • Multi User Systems

3. Single User Systems: • Provides a platform for only one user at a time. • They are popularly associated with Desk Top operating system which run on standalone systems where no user accounts are required. • Example: DOS

4. Multi-User Systems: • Provides regulated access for a number of users by maintaining a database of known users. • Refers to computer systems that support two or more simultaneous users. • Another term for multi-user is time sharing. • Ex: All mainframes and  are multi-user systems. • Example: Unix

5. Contents • Today's Topic:Problem Solving Techniques • We will learn • Problem Statement. • Algorithm • Types, Example • Flowchart • Symbols, Examples.

6. Problem Solving Techniques

7. Problem Statement: Problem Statement help diagnose the situation so that your focus is on the problem, helpful tools at this stage include Algorithms and flowcharts for identifying the expected steps of a process. Therefore to solve any problem, • Collect and analyze information and data • Talk with people familiar with the problem • If at all possible, view the problem first hand • Confirm all findings

8. Algorithm: The algorithm is part of the blueprint or plan for the computer program, an algorithm is: “An effective procedure for solving a class of problems in a finite number of steps.” Every algorithm should have the following 5 characteristic feature: • Input • Output • Definiteness • Effectiveness • Termination

9. Algorithm (Contd…): • To find largest of three numbers • Start • Read 3 numbers: num1, num2, num3 • if num1 > num2 then go to step 5 • if num2 > num3 then print num2 is largest else print num3 is largest goto step 6 • if num1 > num3 then print num1 is largest else print num3 is largest • end.

10. Algorithm (Contd…): Example: One of the simplest algorithms is to find the largest number in an (unsorted) list of numbers. High-level description: • Assume the first item is largest. • 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. • The last noted item is the largest in the list when the process is complete.

11. 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. • largest ← L0for eachitemin the list L, do • if the item > largest, then • largest ← the item • returnlargest

12. Flowchart: What is a Flowchart? • The flowchart is a means of visually presenting the flow of control through an information processing systems, the operations performed within the system and the sequence in which they are performed. • It is a graphic representation of how a process works, showing, at a minimum, the sequence of steps. • Flowcharts are generally drawn in the early stages of formulating computer solutions.

13. Flowchart (Contd…): Guideline for drawing a flowchart: Flowcharts are usually drawn using some standard symbols; Some standard symbols, which are frequently required for flowcharting many computer programs are shown below,-

14. 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.

15. 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.

16. 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.

17. Flow chart of the while loop :

18. Flow chart of the for loop:

19. The flow chart of the if statement:

20. The flow chart of the if…else statement:

21. The flow chart of the switch statement:

22. Flowchart for finding the sum of first five natural numbers ( i.e. 1,2,3,4,5):

23. Flowchart (Example): Flowchart to find the sum of first 50 natural numbers.

24. Flow Chart to find largest of two numbers: Start Read A, B Is A > B Yes No Print B Print A End

25. Flowchart to find the largest of three numbers A,B, and C: NO

26. 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.

27. Flowchart (Exercise): • Draw a flowchart to depict all steps that you do reach your college. • Draw Flowchart for Linear search.