LANGUAGE TRANSLATORS. Workbook. etghallem. St. Aloysius College Computing

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1 LANGUAGE TRANSLATORS Workbook St. Aloysius College Computing

2 Contents Programming Types of Programming Languages... 3 Low Level Languages (LLL)... 3 High Level Languages (HLL)... 3 High Level Languages vs. Low Level Languages... 4 Software Portability... 4 Programming Language Generations... 5 First Generation (LLL)... 5 Second Generation (LLL)... 6 Third Generation (HLL)... 6 Fourth Generation (HLL)... 7 Fifth Generation (HLL)... 8 Language Translators... 9 What is a Translator?... 9 Source Code and Executable Code... 9 Source Code:... 9 Executable Code: Different Types of Translators Assembler Compiler Interpreter Differences between different Translators Ms. J. Cefai / Ms. S. Buttigieg 1

3 Programming What is Programming? Programming is: How can we write programs? Why do we need programming languages? WHAT IS A NATURAL LANGUAGE? Examples: Time flies; If he wins I ll eat my hat! Are Natural Languages suitable as programming languages? Natural languages are as programming languages since they are and with a Ms. J. Cefai / Ms. S. Buttigieg 2

4 What can a computer understand? A computer understands an instruction that is written in a and way. We call such languages, which are basically. Types of Programming Languages Low Level Languages (LLL) Example: High Level Languages (HLL) Example: Ms. J. Cefai / Ms. S. Buttigieg 3

5 High Level Languages vs. Low Level Languages High Level Languages (HLL) Low Level Langugaes (LLL) Easier to program since language is easier to learn, read, write and understand Closer to what Execution is Uses Machine Software Portability What is software portability? Software that can be. Harder to program since language is tougher to read, write and quite longer Closer to what Execution is Uses Machine High Level Languages are since they are not. Low level code of a particular CPU family normally cannot be ported to another family of CPU's since machine code is. Ms. J. Cefai / Ms. S. Buttigieg 4

6 Programming Language Generations Closer to the First Generation (LLL) Closer to Ms. J. Cefai / Ms. S. Buttigieg 5

7 Second Generation (LLL) Also based on machine code, but, easier since it used, which are such as ADD, SUB, DIV, JMP, etc... Programming was easier because the programmer did not have to remember a list of. Needs to be translated into by means of a specific language translator called an. E.g. instead of you write ADD. The assembler will then convert each word into its equivalent bit sequence. Third Generation (HLL) Examples: Ms. J. Cefai / Ms. S. Buttigieg 6

8 Fourth Generation (HLL) Ms. J. Cefai / Ms. S. Buttigieg 7

9 Fifth Generation (HLL) Designed to make the computer solve the problem for you Used mainly in Artificial Intelligence Research (a branch of computer science that studies and develops intelligent machines and software) Examples: On a separate A4 answer the following questions (in your own words) on what was covered so far. 1. Define the term Programming 2. Why do we need Programming Languages? 3. Explain the difference between Natural and Formal language 4. Which language does the computer understand and why? 5. Two types of programming languages are High Level and Low Level. Define each and outline the differences 6. What is Software Portability? 7. Programming Languages evolved into various generations. What are these? Explain each of them and give examples Ms. J. Cefai / Ms. S. Buttigieg 8

10 Language Translators Since computers can only understand machine code (1GL), translators are needed. What is a Translator? Source Code Source Code and Executable Code Source Code: Translat or Executa ble All these statements must be first converted into machine code (1 s and 0 s) so the computer can understand them. Ms. J. Cefai / Ms. S. Buttigieg 9

11 Executable Code: Different Types of Translators There is the need for more than one type of translator: : converts assembly language into machine code : convert higher generation languages into machine code Assembler Converts into Very since assembly is very close to Source Code General functions of an assembler: o Translat or Translate each source code instruction into machine code Executa ble o o o Place program instructions into memory locations Assign the required address Hand over the execution of the program to the Control Unit Ms. J. Cefai / Ms. S. Buttigieg 10

12 Compiler Converts programs into files Dedicated to programming language - a compiler that works for Pascal will not work for C It translates code at Checks the syntax, all libraries used are linked, program is converted to machine code which is then passed to the control unit so that the program is executed Ms. J. Cefai / Ms. S. Buttigieg 11

13 Interpreter Same functions as a compiler, BUT Different since: o It checks each statement o As soon as a statement is coded and Enter is pressed, the interpreter will and inform the programmer of any errors found o It Differences between different Translators Can only be used for 2GL code Must be used for HLL Must be used for HLL Source code is assembled at once Source code is compiled at once Source code is interpreted one line at a time Errors are very difficult to find Errors are difficult to find Errors are easier to find and correct Very fast execution Very fast execution Slow execution Example: Assembly Example: Pascal Example: Basic Ms. J. Cefai / Ms. S. Buttigieg 12