Data Structure and Algorithm 1 Yingcai Xiao. You Me The Course (xiao/dsa1/index.html)

Data Structure and

Algorithm1

Yingcai Xiao

YouMe

The Course(http://www.cs.uakron.edu/~xiao/dsa1/index.html)

The Course

Data Structure?Algorithm?

Computer Science?Computer?

Programming?

What is a Computer?

From the Webster’s New World Dictionary: 1. A person who computes.2. A device used for computing (an electronic machine which by means of stored instructions and information, perform rapid, often complex calculations or compiles, correlates, and selects data).

Computer Science

The science of data processing.

Programming a Computer

Programming a Computer

Types of ComputersAnalog: Analog Device, 1.2345678Digital: Binary Device, 0 or 1

Programming a ComputerWiring: Hardware, Bug, AdaCoding: Software

Modern Computers: Voneumann Machines• Run stored programs (code reuse) to process

stored data.• Components: Memory, IO, CPU, Secondary

Storage.

What is a program and what is programming?

Programs: stored computer instructions for data processing.

Programming

= Data Structures + Algorithms

Professor Donald E. Knuth

http://www-cs-faculty.stanford.edu/~knuth/

What is a program from a computer’s point of view?

Programs: • Stored binary opcodes• Different types of computers have

different opcodes • Opcodes are not reusable on different

types computers • Programs in binary codes are not reusable

on different types of computers

How data are stored on a computer?

Bits (0/1) and bytes (0-255):

Short Int (2 bytes):

0 0 0 0 0 0 1 0

0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

Endian (byte ordering): little (Intel), big (Moterola, Sun), bi (DEC Alpha, MIPS), big-to-bi (Sun SPARK v9)

Is data reusable?

0 1 0 0 0 0 0 1

No, in general.

Is data saved on one type of computers reusable on another type of computers?

Yes, for ASCII text or any type of a byte in size.

‘A’ (65)

ASCII text (ISO/IEC 8859-1) is platform-independent.

What is a program and what is programming?

Programs: stored binary opcodes

Punch Card Programming:

punch card machines

converts instructions typed into binary codes (0 no hole, 1 hole) on a stack of cards.

Programming Languages

Assembly Languages

• English-like: load, add, save

• Assembler: a program that translates code written in an assembly language into opcodes.

• Assembly languages are machine-dependent. An assembly language is only valid for a specific CPU architecture.

• Programs written in an assembly language are machine-dependent and not reusable on a different types of CPU architectures.

High-level Programming Languages

• English-like: if, for, switch, …

• Compiler: a program that translates code written in a high-level programming language into opcodes. The input is called the source code and output is called the object code (.obj).

• Object-codes and executables are machine-dependent.• High-level languages are machine-independent.

• Linker: a program that links object codes together to make an executable (.exe).


• Binary codes are reusable as libraries on computers of the same architecture. (compile-time sharing).

• Object codes (from different high-level programming languages) can be put together to make a library (.lib).

• Libraries (.lib and .dll) are machine-dependent.

• A dynamically-linked library (.dll) can be shared by all programs on the same computer and by all the running processes on the same computer (run-time sharing).

• Libraries and object files on a computer are linked together to form an executable. (compile-time sharing of binary code).


• The header files contain the header (not the implementation) of user defined data types and related methods (functions), i.e., describe what’s in the library.

• To use a library, one needs to include the header files (.h) for the library in the source code.

• The compiler use the information in the header files to make type checking.

• Before compilation, the preprocessor of the compiler copies everything in the header files into the source code and generate an intermediate (.I) file.


• Source codes written in a high-level programming language are reusable on different types of computers.

• Binary codes (.obj, .lib, .dll, .exe) compiled from a high-level programming language are reusable on the computers of the same architecture but not reusable on computers of different architecture.

Traditional Compilation

Source File (.cpp)

Intermediate File (.I)

Object File (.obj)

Binary File (.exe)

Preprocessing

Compilation

Linking

Common Binary Code?(Binary Code Reuse Cross System Architectures)

Traditional Compilation

Source Code for Language 1

Language 1 Compiler on OS1

Binary Code for OS1

OS1



Binary Code for OS2

OS2

OS-Independent Code: Intermediate Languages

The trend to support machine-independent binary code is to compile the source code into the binary format of an intermediate language.

And to provide an interpreter for the intermediate language on each OS to translate the binary code of the intermediate language into the native binary code of the OS.

OS-Independent Compilation: Intermediate Language



Intermediate Binary Code for Language1

OS1

Intermediate Code Interpreter OS1

OS2


Binary Code for OS2Binary Code for OS1

Intermediate Code Interpreter OS2

Java Intermediate Language: Java Bytecode

Java Source Code (.java)

Java Compiler (javac) on OS1

Java Bytecode (.class)

OS1

Java Interpreter on OS1 (java)

OS2



Java Interpreter on OS2 (java)

Program statements are interpreted one at a time during the run-time.

JIT Compiler

An interpreter interprets intermediate code one line at a time. Slow execution.

A JIT (Just-In-Time) compiler compiles the complete code all at once just into native binary code before execution. Faster execution.

JIT Complier: Java Bite Code Compiler

Java Source Code (.java)


Java Bytecode (.class)

OS1

Java JIT Compiler on OS1

OS2



Java JIT Compiler on OS2

All programming statements are compiled at compile time.

.NET OS-Platform-Independence

MSIL: Microsoft Intermediate Language (Used by .NET)



MSIL Code

OS1

MSIL JIT Compiler on OS1

OS2



MSIL JIT Compiler on OS2

JIT Compilation in .NET

All MSIL code are JIT-compiled to native binary code before execution. No run-time interpretation, faster execution.

A Common Language?(Source Code Reuse Cross Languages)

.NET CTS/CLR

.NET Common Language Runtime

To make .NET language independent, CLR (Common Language Runtime) is defined as the runtime environment.

CLR defines CTS (Common Type System) which should be followed by all languages to be used in the .NET framework.

The code that follows CTS standard and runs through CLR is called managed code.

Ex. multiple inheritance is allowed in C++ but not allowed in Managed C++ since CTS doesn’t support it.

.NET Language-Independence

CLR: Common Language Runtime



MSIL Code Confirming CTS (Managed Code)

OS1

CLR on OS1

OS2



CLR on OS2


.NET Architecture for Language and Platform Independence(fan-in and fan-out on MSIL)



OS1

CLR for OS1

OS2



CLR for OS2


MSIL Code Confirming CTS (Managed Code)

Data StructuresAlgorithms

(To be continued)

Documents

Data Structure and Algorithm 1 Yingcai Xiao. You Me The Course (xiao/dsa1/index.html)