%5BM2-GUIDE%5D.pdf

STUDY GUIDE ALGORITHM Algorithm is a procedure or formula for solving a problem, based on conducting a sequence of specified actions. Algorithm can be expressed using pseudocode or flowchart. ALGORITHM OVERVIEW Plan...

STUDY GUIDE ALGORITHM Algorithm is a procedure or formula for solving a problem, based on conducting a sequence of specified actions. Algorithm can be expressed using pseudocode or flowchart. ALGORITHM OVERVIEW Plan the algorithm that will transform the problem’s input into its output. Write the algorithm in the Processing column of the Input-Process-Output (IPO) chart. Each instruction in the algorithm will describe an action that the computer needs to take. Thus, each instruction should start with a verb. ALGORITHM OVERVIEW Most algorithms begin with instruction to enter the input items into the computer. Next, record instructions to process the input items to achieve the problem’s output. The processing typically involves performing one or more calculations using the input items. Most algorithms end with instruction to display, print, or store the output items. Display, print, and store refer to the computer screen, printer, and a file on a disk, respectively. PSEUDOCODE Pseudocode is called false code because, it has no syntax like any of the programming language and thus can’t be compiled or interpreted by the computer. It is simply an implementation of an algorithm in the form of annotations and informative text written in plain English. It is not standardized. Every programmer has his or her own version, but you will find some similarities among other versions. WRITING A PSEUDOCODE In Pseudocode, keywords are used to indicate common input-output and processing operations. They are written fully in uppercase. It also used mathematical, relational and logical operators to express arithmetic and logical operations.  When writing pseudocode, we assume that the order of execution of the statements is from top to bottom. This changes when using control structures, functions and exception handling. WRITING A PSEUDOCODE KEYWORDS: START: This is the start of your pseudocode. INPUT, ENTER, READ / GET : This is data retrieved from the user through typing or through an input device. PRINT, OUTPUT, DISPLAY, SHOW: This will show your output to a screen or the relevant output device. COMPUTE, CALCULATE, DETERMINE: This is used to calculate the result of an expression. SET, INIT: To initialize values INCREMENT, BUMP: To increase the value of a variable DECREMENT: To reduce the value of a variable COMMON OPERATORS: Assignment: ← or := Example: c ← 2πr, c := 2πr Arithmetic: +, −, ×, /, mod Example: a + b, x – y, m x n, s / t, num mod 2 KEYWORDS in CONDITIONAL: During algorithm development, we need statements which evaluate expressions and execute instructions depending on whether the expression evaluated to True or False. Here are some common conditions used in Pseudocode: IF — THEN – ENDIF IF – ELSE IF — ENDIF IF — ELSE IF — ELSE – ENDIF CASE – OTHERS – ENDCASE PSEUDOCODE EXAMPLES BASIC I/O STATEMENT Problem Specification 1: Ms. Noreen wants a program that will calculate and display the amount she should tip a waiter at a restaurant. Tip can be computed by multiplying the total bill and the tip (using a percentage). CONDITIONAL: IF-ELSE STATEMENT Problem Specification 2: Make a program that will display the lowest and highest of two integers entered by the user using if-else statement. CONDITIONAL: CASE STATEMENT Problem Specification 3: Make a program that will ask the user to choose from letters A to C then display the equivalent fruit starting from the selected letter using case statement. ITERATION: FOR LOOP Problem Specification 5: Make a program that will display the sum of three input numbers using for loop statement ITERATION: WHILE LOOP Problem Specification 4: Make a program that will display the sum of three input numbers using while loop statement ITERATION: DO-WHILE LOOP Problem Specification 6: Make a program that will display the sum of three input numbers using do-while loop statement FLOWCHART OVERVIEW Flowchart is a pictorial representation of an ordered, step-by-step solution to a problem. Program Flowchart is a diagram that uses a set of standard graphic symbols to represent the sequence of coded instructions fed into a computer, enabling it to perform specified logical and arithmetical operations. FLOWCHART SYMBOLS Symbol Purpose Description Indicates the flow of logic by connecting Flow line symbols. Represents the start and the end of a Terminal(Stop/Start) flowchart. Input/Output Used for input and output operation. Used for arithmetic operations and Processing data-manipulations. Used for decision making between two Decision or more alternatives.  On-page Connector Used to join different flowline Used to connect the flowchart portion Off-page Connector on a different page. Predefined Represents a group of statements Process/Function performing one processing task. FLOWCHART STRUCTURES Flowcharts can be used to express different structures: sequence selection/conditional loop. Examples of flowcharts in programming: 1. Add two numbers entered by the user. 2. Find the largest among three different numbers entered by the user. 3. Find all the roots of a quadratic equation ax2+bx+c=0 4. Find the Fibonacci series till term≤1000. Note: Though flowcharts can be useful writing and analysis of a program, drawing a flowchart for complex programs can be more complicated than writing the program itself. Hence, creating flowcharts for complex programs is often ignored.