UNIT V - TEXT EDITORS

1. Define interactive editor?

 An interactive editor is a computer program that allows a user to create and revise a target document. The term document includes objects such as computer programs, text, equations, tables, diagrams, line art, and photographs anything that one might find on a printed page. 

2. What are the tasks performed in the editing process? 

4 tasks

 Select the part of the target document to be viewed and manipulated.

 Determine how to format this view on-line and how to display it.

 Specify and execute operations that modify the target document.

 Update the view appropriately.

3. What are the three categories of editor’s devices?

 Text device/ String devices

 Button device/Choice devices

 Locator device

4. What is the function performed in editing phase? 
In the actual editing phase, the target document is created or altered with a set of operations such as insert, delete, replace, move and copy.

5. Define Locator device? 
Locator devices are two-dimensional analog-to-digital converters that position a cursor symbol on the screen by observing the user‟s movement of the device. The most common such devices for editing applications are the mouse and the data tablet.

6. What is the function performed in voice input device?
 Voice-input devices, which translate spoken words to their textual equivalents, may prove to be the text input devices of the future. Voice recognizers are currently available for command input on some systems.


 7. What are called tokens?
The lexical analyzer tracks the source program one character at a time by making the source program into sequence of atomic units is called tokens.

8. Name some of typical tokens. 
Identifiers, keywords, constants, operators and punctuation symbols such as commas and parentheses are typical tokens.

9. What is meant by lexeme?
 The character that forms a token is said to be a lexeme.

10. Mention the main disadvantage of interpreter. 
The main disadvantage of interpreter is that the execution time of interpreted program is slower than that of a corresponding compiled object program.

11. What is meant by code optimization?

 The code optimization is designed to improve the intermediate code, which helps the object program to run faster and takes less space.