Basic of c++ programming

C++ PROGRAMMING An Overview of Computers and Programming Languages

OBJECTIVES In this chapter, you will: Learn about different types of computers Explore the hardware and software components of a computer system Learn about the language of a computer Learn about the evolution of programming languages Examine high-level programming languages 2C++ OVERVIEW: HOW TO START

OBJECTIVES (CONT'D.) Discover what a compiler is and what it does Examine a C++ program Explore how a C++ program is processed Learn what an algorithm is and explore problem-solving techniques Become aware of structured design and object-oriented design programming methodologies Become aware of Standard C++ and ANSI/ISO Standard C++ 3C++ OVERVIEW: HOW TO START

INTRODUCTION Without software, the computer is useless Software developed with programming languages  C++ is a programming language C++ suited for a wide variety of programming tasks Before programming, it is useful to understand terminology and computer components 4C++ OVERVIEW: HOW TO START

A BRIEF OVERVIEW OF THE HISTORY OF COMPUTERS Early calculation devices  Abacus, Pascaline  Leibniz device  Babbage machines: difference and analytic engines  Hollerith machine 5C++ OVERVIEW: HOW TO START

A BRIEF OVERVIEW OF THE HISTORY OF COMPUTERS (CONT'D.) Early computer-like machines  Mark I  ENIAC  Von Neumann architecture  UNIVAC  Transistors and microprocessors 6C++ OVERVIEW: HOW TO START

A BRIEF OVERVIEW OF THE HISTORY OF COMPUTERS (CONT'D.) Categories of computers  Mainframe computers  Midsize computers  Micro computers (personal computers) 7C++ OVERVIEW: HOW TO START

ELEMENTS OF A COMPUTER SYSTEM Hardware CPU Main memory Secondary storage Input/Output devices Software 8C++ OVERVIEW: HOW TO START

HARDWARE CPU Main memory: RAM Input/output devices Secondary storage 9C++ OVERVIEW: HOW TO START

CENTRAL PROCESSING UNIT AND MAIN MEMORY Central processing unit  Brain of the computer  Most expensive piece of hardware  Carries out arithmetic and logical operations 10C++ OVERVIEW: HOW TO START

CENTRAL PROCESSING UNIT AND MAIN MEMORY (CONT'D.) 11C++ OVERVIEW: HOW TO START

CENTRAL PROCESSING UNIT AND MAIN MEMORY (CONT'D.) Random access memory Directly connected to the CPU All programs must be loaded into main memory before they can be executed All data must be brought into main memory before it can be manipulated When computer power is turned off, everything in main memory is lost 12C++ OVERVIEW: HOW TO START

SECONDARY STORAGE Secondary storage: device that stores information permanently Examples of secondary storage:  Hard disks  Flash drives  Floppy disks  Zip disks  CD-ROMs  Tapes 13C++ OVERVIEW: HOW TO START

INPUT/OUTPUT DEVICES Input devices feed data and programs into computers  Keyboard  Mouse  Secondary storage Output devices display results  Monitor  Printer  Secondary storage 14C++ OVERVIEW: HOW TO START

SOFTWARE Software: programs that do specific tasks System programs take control of the computer, such as an operating system Application programs perform a specific task  Word processors  Spreadsheets  Games 15C++ OVERVIEW: HOW TO START

THE LANGUAGE OF A COMPUTER Digital signals: sequences of 0s and 1s Machine language: language of a computer Binary digit (bit):  The digit 0 or 1 Binary code:  A sequence of 0s and 1s Byte:  A sequence of eight bits 16C++ OVERVIEW: HOW TO START

THE LANGUAGE OF A COMPUTER (CONT’D.) 17C++ OVERVIEW: HOW TO START

THE LANGUAGE OF A COMPUTER (CONT'D.) ASCII (American Standard Code for Information Interchange)  128 characters  A is encoded as 1000001 (66th character)  3 is encoded as 0110011 18C++ OVERVIEW: HOW TO START

THE LANGUAGE OF A COMPUTER (CONT'D.) EBCDIC  Used by IBM  256 characters Unicode  65536 characters  Two bytes are needed to store a character C++ OVERVIEW: HOW TO START 19

THE EVOLUTION OF PROGRAMMING LANGUAGES Early computers were programmed in machine language To calculate wages = rates * hours in machine language: 100100 010001 //Load 100110 010010 //Multiply 100010 010011 //Store C++ OVERVIEW: HOW TO START 20

THE EVOLUTION OF PROGRAMMING LANGUAGES (CONT'D.)Assembly language instructions are mnemonic Assembler: translates a program written in assembly language into machine language C++ OVERVIEW: HOW TO START 21

THE EVOLUTION OF PROGRAMMING LANGUAGES (CONT'D.) Using assembly language instructions, wages = rates • hours can be written as: LOAD rate MULT hour STOR wages C++ OVERVIEW: HOW TO START 22

THE EVOLUTION OF PROGRAMMING LANGUAGES (CONT'D.) High-level languages include Basic, FORTRAN, COBOL, Pascal, C, C++, C#, and Java Compiler: translates a program written in a high-level language machine language The equation wages = rate • hours can be written in C++ as: wages = rate * hours; C++ OVERVIEW: HOW TO START 23

PROCESSING A C++ PROGRAM #include <iostream> using namespace std; int main() { cout << "My first C++ program." << endl; return 0; } Sample Run: My first C++ program. C++ OVERVIEW: HOW TO START 24

PROCESSING A C++ PROGRAM (CONT'D.) To execute a C++ program:  Use an editor to create a source program in C++  Preprocessor directives begin with # and are processed by a the preprocessor  Use the compiler to:  Check that the program obeys the rules  Translate into machine language (object program) C++ OVERVIEW: HOW TO START 25

PROCESSING A C++ PROGRAM (CONT'D.) To execute a C++ program (cont'd.):  Linker:  Combines object program with other programs provided by the SDK to create executable code  Loader:  Loads executable program into main memory  The last step is to execute the program C++ OVERVIEW: HOW TO START 26

PROCESSING A C++ PROGRAM (CONT'D.) C++ OVERVIEW: HOW TO START 27

PROGRAMMING WITH THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE Programming is a process of problem solving One problem-solving technique:  Analyze the problem  Outline the problem requirements  Design steps (algorithm) to solve the problem Algorithm:  Step-by-step problem-solving process  Solution achieved in finite amount of time C++ OVERVIEW: HOW TO START 28

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT’D.) Step 1: Analyze the problem  Outline the problem and its requirements  Design steps (algorithm) to solve the problem Step 2: Implement the algorithm  Implement the algorithm in code  Verify that the algorithm works Step 3: Maintenance  Use and modify the program if the problem domain changes C++ OVERVIEW: HOW TO START 29

THE PROBLEM ANALYSIS–CODING– EXECUTION CYCLE (CONT’D.) C++ OVERVIEW: HOW TO START 30

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT'D.) Thoroughly understand the problem Understand problem requirements  Does program require user interaction?  Does program manipulate data?  What is the output? If the problem is complex, divide it into subproblems  Analyze each subproblem as above C++ OVERVIEW: HOW TO START 31

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT'D.) If problem was broken into subproblems  Design algorithms for each subproblem Check the correctness of algorithm  Can test using sample data  Some mathematical analysis might be required C++ OVERVIEW: HOW TO START 32

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT'D.) Once the algorithm is designed and correctness verified  Write the equivalent code in high-level language Enter the program using text editor C++ OVERVIEW: HOW TO START 33

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT'D.) Run code through compiler If compiler generates errors  Look at code and remove errors  Run code again through compiler If there are no syntax errors  Compiler generates equivalent machine code Linker links machine code with system resources C++ OVERVIEW: HOW TO START 34

THE PROBLEM ANALYSIS– CODING–EXECUTION CYCLE (CONT'D.) Once compiled and linked, loader can place program into main memory for execution The final step is to execute the program Compiler guarantees that the program follows the rules of the language  Does not guarantee that the program will run correctly C++ OVERVIEW: HOW TO START 35

EXAMPLE 1-1 Design an algorithm to find the perimeter and area of a rectangle The perimeter and area of the rectangle are given by the following formulas: perimeter = 2 * (length + width) area = length * width C++ OVERVIEW: HOW TO START 36

EXAMPLE 1-1 (CONT'D.) Algorithm:  Get length of the rectangle  Get width of the rectangle  Find the perimeter using the following equation: perimeter = 2 * (length + width)  Find the area using the following equation: area = length * width C++ OVERVIEW: HOW TO START 37

EXAMPLE 1-3 Every salesperson has a base salary Salesperson receives $10 bonus at the end of the month for each year worked if he or she has been with the store for five or less years The bonus is $20 for each year that he or she has worked there if over 5 years C++ OVERVIEW: HOW TO START 38

EXAMPLE 1-3 (CONT'D.) Additional bonuses are as follows:  If total sales for the month are $5,000-$10,000, he or she receives a 3% commission on the sale  If total sales for the month are at least $10,000, he or she receives a 6% commission on the sale C++ OVERVIEW: HOW TO START 39

EXAMPLE 1-3 (CONT'D.) Get baseSalary Get noOfServiceYears Calculate bonus using the following formula: if (noOfServiceYears is less than or equal to five) bonus = 10 * noOfServiceYears otherwise bonus = 20 * noOfServiceYears Get totalSales C++ OVERVIEW: HOW TO START 40

EXAMPLE 1-3 (CONT'D.) Calculate additionalBonus as follows: if (totalSale is less than 5000) additionalBonus = 0 otherwise if (totalSale is greater than or equal to 5000 and totalSale is less than 10000) additionalBonus = totalSale · (0.03) otherwise additionalBonus = totalSale · (0.06) C++ OVERVIEW: HOW TO START 41

EXAMPLE 1-3 (CONT'D.) Calculate payCheck using the equation payCheck = baseSalary + bonus + additionalBonus C++ OVERVIEW: HOW TO START 42

EXAMPLE 1-5 10 students in a class Each student has taken five tests and each test is worth 100 points Design an algorithm to calculate the grade for each student as well as the class average  Design an algorithm to find the average test score  Design an algorithm to determine the grade Data consists of students’ names and their test scores C++ OVERVIEW: HOW TO START 43

EXAMPLE 1-5 (CONT'D.) Algorithm to determine the average test score:  Get the five test scores  Add the five test scores  Suppose sum stands for the sum of the test scores  Suppose average stands for the average test score:  average = sum / 5; C++ OVERVIEW: HOW TO START 44

EXAMPLE 1-5 (CONT'D.) Algorithm to determine the grade: if average is greater than or equal to 90 grade = A otherwise if average is greater than or equal to 80 and less than 90 grade = B otherwise if average is greater than or equal to 70 and less than 80 grade = C otherwise if average is greater than or equal to 60 and less than 70 grade = D otherwise grade = F C++ OVERVIEW: HOW TO START 45

EXAMPLE 1-5 (CONT'D.) Main algorithm is as follows:  totalAverage = 0;  Repeat the following for each student:  Get student’s name  Use the algorithm to find the average test score  Use the algorithm to find the grade  Update totalAverage by adding current student’s average test score  Determine the class average as follows:  classAverage = totalAverage / 10 C++ OVERVIEW: HOW TO START 46

PROGRAMMING METHODOLOGIES Two popular approaches to programming design  Structured  Object-oriented C++ OVERVIEW: HOW TO START 47

STRUCTURED PROGRAMMING Structured design:  Dividing a problem into smaller subproblems Structured programming:  Implementing a structured design The structured design approach is also called:  Top-down (or bottom-up) design  Stepwise refinement  Modular programming C++ OVERVIEW: HOW TO START 48

OBJECT-ORIENTED PROGRAMMING Identify components called objects Specify relevant data and possible operations to be performed on that data Each object consists of data and operations on that data An object combines data and operations on the data into a single unit C++ OVERVIEW: HOW TO START 49

OBJECT-ORIENTED PROGRAMMING (CONT'D.) A programming language that implements OOD is called an object-oriented programming (OOP) language Learn how to represent data in computer memory, how to manipulate data, and how to implement operations Write algorithms and implement them in a programming language C++ OVERVIEW: HOW TO START 50

OBJECT-ORIENTED PROGRAMMING (CONT'D.) Learn how to combine data and operations on the data into a single unit called an object C++ was designed to implement OOD OOD is used with structured design C++ OVERVIEW: HOW TO START 51

ANSI/ISO STANDARD C++ C++ evolved from C C++ designed by Bjarne Stroustrup at Bell Laboratories in early 1980s C++ programs were not always portable from one compiler to another In mid-1998, ANSI/ISO C++ language standards were approved C++ OVERVIEW: HOW TO START 52

SUMMARYComputer: electronic device that can perform arithmetic and logical operations Computer system has hardware and software Central processing unit (CPU): brain Primary storage (MM) is volatile; secondary storage (e.g., disk) is permanent Operating system monitors the overall activity of the computer and provides services C++ OVERVIEW: HOW TO START 53

SUMMARY (CONT'D.) Various kinds of languages, such as machine language, assembly, high- level Algorithm: step-by-step problem- solving process; solution in finite amount of time Problem-solving process has three steps:  Analyze problem and design an algorithm  Implement the algorithm in code  Maintain the program C++ OVERVIEW: HOW TO START 54

SUMMARY (CONT'D.) Structured design:  Problem is divided into smaller subproblems  Each subproblem is solved  Combine solutions to all subproblems Object-oriented design (OOD): a program is a collection of interacting objects  Object: data and operations on those data C++ OVERVIEW: HOW TO START 55

Basic of c++ programming

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