Data Structure and Algorithm 1

1. Data Structure andAlgorithm1 Yingcai Xiao

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

3. Data Structure? Algorithm? Computer Science? Computer? Programming? The Course

4. 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). What is a Computer?

5. The science of data processing. Computer Science

6. Programming a Computer

7. Types of Computers Analog: Analog Device, 1.2345678 Digital: Binary Device, 0 or 1 Programming a Computer Wiring: Hardware, Bug, Ada Coding: Software Programming a Computer • Modern Computers: Voneumann Machines • Run stored programs (code reuse) to process stored data. • Components: Memory, IO, CPU, Secondary Storage.

8. 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 and what is programming?

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

10. Bits (0/1) and bytes (0-255): Short Int (2 bytes): How data are stored on a computer? Endian (byte ordering): little (Intel), big (Moterola, Sun), bi (DEC Alpha, MIPS), big-to-bi (Sun SPARK v9)

11. Is data saved on one type of computers reusable on another type of computers? No, in general. Yes, for ASCII text or any type of a byte in size. Is data reusable? ASCII text (ISO/IEC 8859-1) is platform-independent. ‘A’ (65)

12. 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. What is a program and what is programming?

13. Programming Languages

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

15. 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). • Linker: a program that links object codes together to make an executable (.exe). High-level Programming Languages • Object-codes and executables are machine-dependent. • High-level languages are machine-independent.

16. Object codes (from different high-level programming languages) can be put together to make a library (.lib). • Binary codes are reusable as libraries on computers of the same architecture. (compile-time sharing). • Libraries and object files on a computer are linked together to form an executable. (compile-time sharing of binary code). High-level Programming Languages • 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 (.lib and .dll) are machine-dependent.

17. To use a library, one needs to include the header files (.h) for the library in the source 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. • The compiler use the information in the header files to make type checking. High-level Programming Languages • Before compilation, the preprocessor of the compiler copies everything in the header files into the source code and generate an intermediate (.I) file.

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

19. Source File (.cpp) Preprocessing Compilation Linking Intermediate File (.I) Object File (.obj) Binary File (.exe) • Traditional Compilation

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

21. Source Code for Language 1 Source Code for Language 1 Language 1 Compiler on OS1 Language 1 Compiler on OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2 • Traditional Compilation

22. 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 Code: Intermediate Languages

23. OS-Independent Compilation: Intermediate Language Source Code for Language 1 Language 1 Compiler on OS1 Language 1 Compiler on OS2 Intermediate Binary Code for Language1 Intermediate Code Interpreter OS1 Intermediate Code Interpreter OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2

24. Java Intermediate Language: Java Bytecode Java Source Code (.java) Java Compiler (javac) on OS1 Java Compiler (javac) on OS2 Java Bytecode (.class) Program statements are interpreted one at a time during the run-time. Java Interpreter on OS1 (java) Java Interpreter on OS2 (java) Binary Code for OS1 Binary Code for OS2 OS1 OS2

25. 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 Compiler

26. JIT Complier: Java Bite Code Compiler Java Source Code (.java) Java Compiler (javac) on OS1 Java Compiler (javac) on OS2 Java Bytecode (.class) All programming statements are compiled at compile time. Java JIT Compiler on OS1 Java JIT Compiler on OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2

27. MSIL: Microsoft Intermediate Language (Used by .NET) Source Code for Language 1 Language 1 Compiler on OS1 Language 1 Compiler on OS2 MSIL Code .NET OS-Platform-Independence MSIL JIT Compiler on OS1 MSIL JIT Compiler on OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2

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

29. A Common Language? (Source Code Reuse Cross Languages) .NET CTS/CLR

30. 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 Common Language Runtime

31. CLR: Common Language Runtime Source Code for Language 1 Source Code for Language 2 Language 1 Compiler on OS1 Language 2 Compiler on OS2 MSIL Code Confirming CTS (Managed Code) .NET Language-Independence CLR on OS1 CLR on OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2

32. Source Code for Language 1 Source Code for Language 2 Language 1 Compiler on OS1 Language 2 Compiler on OS2 MSIL Code Confirming CTS (Managed Code) .NET Architecture for Language and Platform Independence (fan-in and fan-out on MSIL) CLR for OS1 CLR for OS2 Binary Code for OS1 Binary Code for OS2 OS1 OS2

33. Data Structures Algorithms (To be continued)