Algorithms and Pseudocode Overview

Problem Analysis

• A programming task can be broken down into two phases: problem solving and implementation.
• The problem solving phase involves creating an ordered sequence of steps to solve a problem, known as an algorithm.
• The implementation phase involves translating the algorithm into a specific programming language.

Algorithms and Pseudocode

• Pseudocode is an informal, artificial language used to develop algorithms.
• It resembles everyday English and assists programmers in outlining the steps involved in a program.
• Example: Calculating a student’s final grade based on four marks using pseudocode:
  • Input four marks.
  • Calculate the average by summing the marks and dividing by 4.
  • If the average is below 50, print “FAIL”. Otherwise, print “PASS”.

Flowcharts

• A flowchart is a visual representation of an algorithm.
• It emphasizes individual steps and their connections.
• It illustrates the flow of control between actions in a program.

Flowchart Symbols

• Oval: Denotes the start or end of a program.
• Parallelogram: Represents an input operation.
• Rectangle: Represents a process to be carried out, like addition, subtraction, or division.
• Diamond: Represents a decision or branch. The program follows one of two paths based on the decision.
• Hybrid: Represents an output operation.
• Flow line: Shows the direction of logic flow in the program.

Example Flowchart

• The flowchart for calculating a student's grade:
  • Start
  • Input: M1, M2, M3, M4
  • Process: GRADE  (M1+M2+M3+M4)/4
  • Decision: if (GRADE < 50)
    • Output: Print “FAIL”
  • Decision: else
    • Output: Print “PASS”
  • End