Programming in C++

1. Prerequisite: CS1 or some programming experience Text: C++ How to Program, Deitel & Deitel Programming in C++ C++ Course SarMag Trimester 3

2. Computers and Programs • A simplified model of a computer consists of a processing unit (CPU) and a memory. • CPU can understand simple instructions: • read/write a memory location • add two numbers • compare numbers • etc. C++ Course SarMag Trimester 3

3. Machine Code • An executable program is a sequence of these simple instructions. • The sequence is stored in memory. • The CPU processes the simple instructions sequentially. • Some instructions can tell the CPU to jump to a new place in memory to get the next instruction. C++ Course SarMag Trimester 3

4. Instructions • Each instruction is stored in memory as a bunch of bits. • The CPU decodes the bits to determine what should happen. • For example, the instruction to add 2 numbers might look like this: 10100110 C++ Course SarMag Trimester 3

5. Memory • The Memory can hold programs and data. • Each piece of data is also just a bunch of bits. • Typically the memory is organized in chunks of 8 bits (called a byte). • Each chunk (byte) has an address. C++ Course SarMag Trimester 3

6. MEMORY Address 0 1 2 3 4 5 81345 81346 81347 ... ... A Picture CPU ... ... C++ Course SarMag Trimester 3

7. Sample Program # Instruction 1 Set memory[801] to hold 00000001 2 Set memory[802] to hold 00000000 3 If memory[802] = 10 jump to instruction #8 4 increment memory[802] 5 set memory[803] to 2 times memory[801] 6 put memory[803] in to memory[801] 7 jump to instruction #3 8 print memory[801] C++ Course SarMag Trimester 3

8. Another Picture MEMORY Address 0 1 2 3 4 5 801 802 803 Instruction #1 Instruction #2 CPU Instruction #3 Instruction #4 Instruction #5 Instruction #6 ... ... C++ Course SarMag Trimester 3

9. Human vs Machine Programs • The computer can only understand the bits (the encoded program) • Humans don't like to deal with bits, so they developed english-like abbreviations for programs. Machine Language Assembly Language C++ Course SarMag Trimester 3

10. Assembly & Machine Language Assembly Language Machine Language 00100101 11010011 00100100 11010100 10001010 01001001 11110000 01000100 01010100 01001000 10100111 10100011 11100101 10101011 00000010 00101001 11010101 11010100 10101000 10010001 01000100 ST 1,[801] ST 0,[802] TOP: BEQ [802],10,BOT INCR [802] MUL [801],2,[803] ST [803],[801] JMP TOP BOT: LD A,[801] CALL PRINT C++ Course SarMag Trimester 3

11. An Assembler Assembler Assembly Language Program ST 1,[801] . . . Machine Language Program 01001001 10010100 C++ Course SarMag Trimester 3

12. Higher-Level Languages • Assembly Language is much easier to deal with than Machine Language, but you need to know about all the instructions. • People developed languages that were independent of the specific machine language. • More abstract representation of instructions. C++ Course SarMag Trimester 3

13. High-Level Languages • Many high-level languages have been developed. • Different ways of representing computations. • Different languages for different needs: • symbolic vs. numeric computation • human efficiency vs. program efficiency • portability • extensibility C++ Course SarMag Trimester 3

14. C++ • C++ is an extension of C. • C++ was first developed in the early 1980s (back in the last century!). • Focus was on Object Oriented Programming • view computer programs as collection of objects. • Objects have attributes and actions. C++ Course SarMag Trimester 3

15. As a C/C++ program set memory[801] to hold 00000001 set memory[802] to hold 00000000 if memory[802] = 10 jump to instruction #8 increment memory[802] set memory[803] to 2 times memory[801] put memory[803] in to memory[801] jump to instruction #3 print memory[801] x=1; i=0; while (i!=10) { i++; x=x*2; } printf("%d",x); } C++ Course SarMag Trimester 3

16. Compiler C++ Compiler C++ Program int main() { int i=1; . . . Machine Language Program 01001001 10010100 Created with text editor or development environment C++ Course SarMag Trimester 3

17. Many Different Compilers • There are many different C++ Compilers: • Microsoft Visual C++ • Borland C++ • GNU g++ • IBM xlc • Sun CC C++ Course SarMag Trimester 3

18. What is an Algorithm? • Algorithm = Calculation Procedure • The traditional definition of "algorithm" is that it is a formally defined procedure for performing some calculation • A finite ordered set of well defined rules for the solution of a problem. Algorithms are often written in pseudocode, so that they can be easily converted in many different programming languages C++ Course SarMag Trimester 3

19. What is an Algorithm? • algorithm is a set of step-by-step commands or instructions designed to reach a particular goal • algorithmA mathematical procedure used to solve problems with a series of steps. C++ Course SarMag Trimester 3

20. Properties of Algorithms • 1. Finiteness/ Terminate • 2. Absence of Ambiguity • 3. Definite/ Clear • 4. Efective • 5. Input • 6. Output (KNU-69, HOR-90) C++ Course SarMag Trimester 3

21. Prinsip Pemrograman • Harus dapat menentukan masalah sesungguhnya. • Design program • Struktur data • Coding program • Testing program • Pemeliharaan program + Dokumentasi C++ Course SarMag Trimester 3

22. Aturan pemrograman • Buat dokumentasi • Buat semudah mungkin • Gunakan modul jika dirasa program cukup besar • Gunakan fungsi untuk suatu hal yg sering di gunakan • Hindari penggunaan var global C++ Course SarMag Trimester 3