Sequential vs. Event-driven Programming
Reacting to the user
Outline
Sequential programming GUI program organization Event-driven programming Modes
Sequential Programming
In sequential programs, the program is under control The user must synchronize with the program:
Program tells user it is ready for input User enters input and it is processed
Examples:
Command-line prompts (DOS, UNIX) LISP interpreters
Shouldn’t the program be required to synchronize with the user?
Sequential Programming (2)
Flow of a typical sequential program
Prompt the user Read input from the keyboard Parse the input (determine user action) Evaluate the result Generate output Repeat
Example
DemoTranslateEnglishConsole.java
Prompt the
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Interfaces vs. Classes
The definition of a class includes both the design of the class and its implementation Sometimes it is desirable only to design a class, leaving the implementation for later This is accomplished using an interface An interface contains only the design of a class
Includes signatures for its members (methods and fields) No implementation is provided
Characteristics of Interfaces
Interfaces… Do not have instance variables You cannot instantiate an object of an interface Include only abstract methods Methods have a signature (i.e., a name, parameters, and return type) Methods do not have an implementation (i.e., no code) Include only public methods and fields Does not make sense to define private members if the public members that could potentially use them are themselves not implemented
Listener Example
The signature of our extended JFrame class includes the clause implements KeyListener This means our class must include definitions for the methods of the KeyListener listener Thus… public void keyPressed(KeyEvent ke) {} public void keyReleased(KeyEvent ke) {} public void keyTyped(KeyEvent ke) {}
Our implementation includes the code we
When the user begins to interact with the computer, the software being used will send out a system call that will specify a task that a hardware component must perform in order for the software to continue functioning and send further requests,
M1 - Describe the features of an event driven language that make it suitable for creating a GUI
How do we define a “concept” in our field? (2 points) Hint: this resembles a mathematical equation.
In order for IT System to become active first Computer Programs and Programming must be put in place. Computer Programs and Programming are simple terms an executable set of commands for the computer to perform. A process is an actively running program which may or may not is running in the background. A program running in the background is one that the computer user may not be aware of, but it may be providing useful services such as an ability to connect to other computers. It reads and executes program instructions, performs calculations, and makes decisions (slideshare.net).
System shаll show the error messаge to the user when the input given is not in the required formаt.
For each of the two programming problems, create a program using Visual C++.Net. Make sure to capture a sample of your program's output. The best way to do this is to click on the console window you want to capture and then press the Alt and PrintScreen keys at the same time. Then paste your captured screen image into a Word document. For each of the two programs, put the screen capture followed by a copy of your source code into your Word document.
Processing Logic – The logic used in this program is based on Iif- Tthen statements. From the begging in of the program the season input will enact a series of Iif-T then statements that the one that happens to be true for that input will then move the program to the appropriate module. Within the modules each question has iIf t-Then and eElse statements stating that if the home owner makes a certain input the program will calculate the out put.
We were assigned to construct a software that utilizes a classification algorithm that is able to accurately decide a correct classification for a certain sequence of inputs that were provided by the user. The input is to be classified based on a known training set of records of the same attributes as the sequence provided by the user.
It consist of three parts: 1. Name of the class 2. Attributes of the class 3. Operations of the class.
1. Customers place their order on-line, and when they press the "submit" button, it signals the order fulfillment software to swing into action. Coding of book
Describe the steps to be taken prior to inputting the data into the computerized system and how you would go about implementing the new system.
Each programming language uses a piece of software, called a compiler or an interpreter, to translate your program code into machine language. Machine language is also called binary language, and is represented as a series of 0s and 1s. The compiler or interpreter that translates your code tells you if any programming language component has been used incorrectly. Syntax errors are relatively easy to locate and correct because the compiler or interpreter you use highlights every syntax error. If you write a computer program using a language such as C++ but spell one of its words incorrectly or reverse the proper order of two words, the software lets you know that it found a mistake by displaying an error message as soon as you try to translate the program.
To begin some definitions need to be established for the paper, so the reader can logically follow.
a. Design the logic for a program that allows a user to enter 10 numbers, then
A variable y is being set, then the code enters a loop. this is showing procedural programing as it defines what the computer should do step by step.