Pseudocode syntax, descriptions and examples

Transcription

1 Pseudocode syntax, descriptions and examples Overview: This table provides a reference for commonly used pseudocode for introductory computer program design courses. You should use this as your reference and copy and paste code examples into your projects to ensure you are using proper syntax. Be sure to indent your code to make it more readable and use modify and enhance from the examples as needed. Also, capitalize the first letter of your pseudocode (e.g. While, not while). Pseudocode Description Flowchart equivalent Example usage /Prompt Displays messages and other information on the screen What is your name? What is your name? Your name is +YourName +. Prompt for ItemName, Price, Quantity Input Pauses execution, allowing the user to enter data Input FirstName Input FirstName Input Number1, Number2 Compute/Set Assigns a value to a variable Compute average value: Set Avg=(num1+num2)/2 Set Avg= (num1 + num2)/2 Compute total cost: Set TotalCost= 1.25*Songs Declare Declares a variable to be of a specific type Declare FirstName as String Declare FirstName As String Declare Num1, Num2 As Integer Possible datatypes may include: String 1

2 Call Requests a module, subprogram, or function be executed Call Nums(num1, num2)) Character Integer Float Main Module 2 numbers Input Num1,Num2 Call Nums(num1,num2) Program complete Subprogram Nums(Float num1, Float num2) Num1 is + num1 Num2 is + num2 End Subprogram If Tests if a condition is met. If the test condition is true, the statements are executed. Input Number If Number < 5 Then OK Is Number < 5? OK 2

3 If Else Tests If a condition is true. If the test condition is true one set of statements are executed, else, the other set of statements are executed. Is Age > 18? Input Age If Age > 18 Then You are an Adult Else You are Young You are an Adult You are Young Select Case End Case Tests a condition against multiple values executing the code with appropriate matching value, skipping all other code blocks. A Excellent B Good Value of Grade F Failure Select Case Of Grade Case A: Excellent Case B: Good Case C: Average Case D: Poor Case F: Failure End Case 3

4 Repeat Until Repeats execution of code until the condition is true. (Post-Test loop) Input Number Repeat Input Number Until Number==0 List Ended Is Number ==0? List Ended 4

5 While End While Repeats execution of code as long as the condition is true. (Pre-Test loop) Is Number < 10? Set Number=0 While Number < 10 Set Number=Number+1 End While Program complete Set Number = Number + 1 Program Complete For End For Repeats execution of code as long as the condition is true. (Pre-Test loop). Counter is often included in the declaration. Set Num=0 Declare Num as Integer For( Num=0; Num<10; Num++) Num is + Num End For Is Num<10? Num is + Num Num=Num+1 5

6 Main Groups programming statements into the main module Main Hello World Welcome to Class End Hello World Welcome to Class Subprogram End Subprogram Groups programming statements into a Subprogram that is often called from another Subprogram,function or Module (te: Flowchart for Programming statements for the WelcomeMessage Subprogram are not shown) Words Input Words Call WelcomeMessage(Words) Main Words Input Words Call WelcomeMessage (Words) Subprogram WelcomeMessage (String Words) Words are + Words End Subprogram 6

7 Function End Function Groups programming statements into a function that is often called from another Subprogram, function or Module (te: Flowchart for Programming statements for the AreaofSquare function are not shown) Declare AreaofSquare as Float Set AreaofSquare = Area(5) Main Declare AreaofSquare as Float Set AreaofSquare= Area(5) Function Area (Side) As Float Set Area= Side * Side End Function 7