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Understanding Algorithms and Program Development Process

Explore the Software Development Life Cycle, algorithms, pseudocode, and program design. Learn the importance of problem-solving, sequencing, selection, and looping structures. Practice exercises provided.

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Understanding Algorithms and Program Development Process

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  1. Chapter 3 :Basic Concepts of Algorithm Prepared by Madam ZanariahIdrus

  2. Outline • Software Development Life Cycle • Algorithm • Pseudocode • Exercises

  3. Six step procedure • Program specification • Program design • Program code • Program test • Program documentation • Program maintenance Software Development Life Cycle (SDLC) Page 398

  4. Understanding what the problem is? • What is solution should provide? • Inputs to the problem • Any special constraints/condition/ formulas to be used • 75% of total lifetime cost • Error-free operations • Effective program • Two categories • Operations • Changing needs • Plan a solution • Using Algorithm: - Pseudocode - Flowcharts • Written descriptions and procedures about a program • User manual • Transform design to coding • Writing the program or coding SDLC • Debugging • Syntax errors • Logic errors

  5. Pseudo code • a semi formal English – like language with a limited vocabulary, used to design & describe algorithm • Flowchart • a graph consisting of geometrical shapes that are connected by flow lines, used to design & describe algorithm Algorithms

  6. Problem Program Code Algorithm : A sequence of instructions describing how to do a task (or process) From Algorithms to Programs

  7. Both are sets of instructions on how to do a task • Algorithm: • talking to humans, easy to understand • in plain (English) language • Program: • talking to computer (compiler) • can be regarded as a “formal expression” of an algorithm From Algorithms to Programs

  8. Pseudocode Begin Read number1 Read number2 Add number1 & number2 Display sum End • An outline of the logic for your program • A summary of the program Page 403

  9. Flowchart Page 403

  10. SEQUENCE STRUCTURE SELECTION STRUCTURE LOOP STRUCTURE Flowchart: Logic Structures Page 404

  11. Why algorithm is important? • Describe the steps needed to perform a computation • Important for writing efficient code • code that execute faster & which uses less memory

  12. With sequence structure, an action or event is performed in order, one after another. • A sequence can contain any number of events but there is no chance to branch off and skip any of the events. • Once you start a series of events in a sequence, you must continue step‐by‐step until the sequence ends. Sequence Structure

  13. Problem: • Design a software to calculate the sum of two numbers entered by user. Example 1: sequence

  14. (flowchart) (pseudo code) Steps: • Begin • Read no1 • Read no2 • Add no1 & no2 • Display sum • End start Read no1 Read no2 Display Sum answer=no1+no2 end Example: Add 2 numbers

  15. Example 1 answer

  16. EXERCISES

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