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Programming HSPM J713 Programming languages and systems PowerPoint PPT Presentation


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Programming languages generally come with programming system. The language part of a programming language is the key words, symbols, and syntax used to write code. ... - PowerPoint PPT Presentation

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Programming HSPM J713 Programming languages and systems

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Programming l.jpg

Programming

HSPM J713


Programming languages and systems l.jpg

Programming languages and systems

  • Programming languages generally come with programming system

  • The language part of a programming language is the key words, symbols, and syntax used to write code.

  • The system part translates the written code into machine instructions that computer executes. Can be a compiler or an interpreter.


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Platform-specific

  • Language system works with specific hardware

  • The “IBM-compatible” PC or the Windows PC

  • All use the same:

    • Machine instructions (which depends on chip architecture)

    • Memory, screen


Assembly language l.jpg

Assembly language

mov ax, 1234h

mov bx, ax

Directly translates into machine code (binary numbers)

Compiler translates all instructions in program into machine code

Low level – explicitly manipulates registers (places to hold data) on the CPU chip.

Each chip has its own assembly language


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FORTRAN

Do 10 j = 2 , 1000

B(j) = A(j-1)

A(j-1)=j

10 continue

Compiled into machine language and then run

Used on mainframes since 1950’s.

Designed for math


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BASIC

Beginner's All-purpose Symbolic Instruction Code

For students and general users

Interpreted – One line at a time is translated into machine code and executed


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BASIC – unstructured, interpreted

10 INPUT "What is your name: ", U$

20 PRINT "Hello "; U$

30 INPUT "How many stars do you want: ", N

40 S$ = ""

50 FOR I = 1 TO N

60 S$ = S$ + "*"

70 NEXT I

80 PRINT S$

90 INPUT "Do you want more stars? ", A$

100 IF LEN(A$) = 0 THEN 90

110 A$ = LEFT$(A$, 1)

120 IF A$ = "Y" OR A$ = "y" THEN 30

130 PRINT "Goodbye ";U$

140 END


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BASIC structured, compiled

INPUT "What is your name: ", UserName$

PRINT "Hello "; UserName$

DO

INPUT "How many stars do you want: ", NumStars

Stars$ = STRING$(NumStars, "*")

PRINT Stars$

DO

INPUT "Do you want more stars? ", Answer$

LOOP UNTIL Answer$ <> ""

Answer$ = LEFT$(Answer$, 1)

LOOP WHILE UCASE$(Answer$) = "Y"

PRINT "Goodbye "; UserName$


Slide9 l.jpg

C, C++

  • This Hello world program uses the C++ standard library stream facility to write a message to standard output:

    #include <iostream> // provides std::cout

    int main() {

    std::cout << "Hello, world!\n";

    }

    Uses “library” of code, callable with key words, to execute complex tasks

    Compiler for specific platform translates that into machine code.


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Java

  • Compiled code runs on Virtual Machine

  • A virtual machine is written for each platform.

    • The virtual machine for a platform translates virtual machine instructions into machine instructions for that platform

    • Java runs on PC virtual machine on PC’s, Macintosh virtual machine on Macs, for example.

  • So compiled Java code can run on many platforms. Good for web applications.


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Java resembles C in syntax

Class HelloWorld {

public static void main (String[] arguments) {

System.out.println(“Hello World!”);

}

}

Compiled using Java Development Kit


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Java uses objects

import java.applet.*;

import java.awt.*;

public class TextEntry extends Applet {

TextField Reply;

TextField Entry;

public void init() {

setBackground(Color.white);

add("EntryLabel", new Label("Type your number in the small box and press Enter:"));

add("Entry", Entry = new TextField("", 5));

add("Reply", Reply = new TextField("My reply will appear here.", 60));

Reply.setEditable(false);

}

public void compute() {

int value;

try {

value = Integer.valueOf(Entry.getText().trim()).intValue();

if (value == 15) {

Reply.setText("Correct! 15 is right!");

}

else {

if (value > 15) Reply.setText(Entry.getText()+" is too high.");

if (value < 15) Reply.setText(Entry.getText()+" is too low.");

}

} catch(NumberFormatException e) {

Reply.setText(Entry.getText() + " is not a number.");

}

}

public boolean action(Event e, Object dummy) {

compute();

return(true);

}

}

Textentry example


Java uses objects13 l.jpg

Java uses objects

import java.applet.*;

import java.awt.*;

public class TextEntry extends Applet {

TextField Reply;

TextField Entry;

}


Java uses objects14 l.jpg

Java uses objects

public class TextEntry extends Applet {

TextField Reply;

TextField Entry;

public void init() {

setBackground(Color.white);

add("EntryLabel", new Label("Type your number in the small box and press Enter:"));

add("Entry", Entry = new TextField("", 5));

add("Reply", Reply = new TextField("My reply will appear here.", 60));

Reply.setEditable(false);

}

}


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Java uses objects

public void compute() {

int value;

try {

value = Integer.valueOf(Entry.getText().trim()).intValue();

if (value == 15) { Reply.setText("Correct! 15 is right!"); }

else {

if (value > 15) Reply.setText(Entry.getText()+" is too high.");

if (value < 15) Reply.setText(Entry.getText()+" is too low.");

}

}

catch(NumberFormatException e) { Reply.setText(Entry.getText() + " is not a number.");}

}

public boolean action(Event e, Object dummy) {

compute();

return(true);

}

}