Chapter 1Computer HardwareComputer ProgramProgramming LanguagesTypes of InstructionsTypes of Computer SoftwareAlgorithmAlgorithms continuedComputer Problem Solving StepsHow to run or execute (test) a C++ programTurbo C/C++ program development environmentA simple C++ programA simple C++ program continuedAnother simple program. What does it do?C++ language elements (tokens)Tokenize the above programsQuestion?Divide and conquer: a modular approach to a complex problemChapter 1Introduction to ProgrammingComputer Hardware•CPU•Memory–Main or primary–Secondary or auxiliary•Input device(s)•Output device(s)Computer Program•A list of instructions that direct the computer hardware to perform a particular data processing tack or solve a specific problem. The program is coded in a particular programming language such as C++, Fortran, and Visual Basic.•Software = a program or a collection of programsProgramming Languages•Low level machine language: 0’s and 1’s; the native language of the machine; machine-dependent.•Intermediate level assembler language: mnemonics; suggestive symbols or letters; Machine dependent; requires translator known as assembler.•High level procedural language: resembles English and/or standard notation of math; machine-independent (portable); requires translator known as compiler or interpreter.Types of Instructions•Input: e.g., cin in C++•Process: many operator including +, -, *, / to perform arithmetic and other types of processing.•Output: e.g., cout in C++Types of Computer Software•Systems software–Operating system: Windows, Unix–Compiler: C/C++ compiler–…•Applications software–Payroll program: usually custom-designed/developed.–Airline reservation software: usually custom-designed/developed; very expensive.–Word processor: perform generic word-processing tasks for general consumers.Algorithm•Step-by-step instructions that lead to the solution of a problem.•Example: What is the algorithm that computes the average of three arbitrary values? What is the algorithm that adds integers from 1 to 100? (not unique! Some are better or more efficient that others. Efficient in what sense?)Algorithms continued•Tools to help develop/specify/visualize an algorithm–Flowchart: a set of symbols (p9); less popular today but helpful to beginners to visualize the steps.–Pseudocode: informal English statements; easier to convert to a program using a structured programming language such as C or Fortran.Computer Problem Solving Steps1. Understand/formulate/specify the problem2. Develop the algorithm, which is independent of computer languages.3. Convert the algorithm to a program (Computer language must be chosen)4. Test/debug (steps 1 thru 4 may be iterative)5. DeliverHow to run or execute (test) a C++ program•Need a C++ translator known as a compiler, which convert C++ source program (or source code) to machine language program (or object code).•There are several popular C/C++ compilers available commercially or in the public domain: Borland/Turbo C/C++, Microsoft Visual C/C++, gcc compiler, etc.Turbo C/C++ program development environment•The Integrated Development Environment or IDE–Editor–Preprocessor and compiler–Debugger–OthersA simple C++ program•The program displays/prints a greeting message “Hello World”•Steps 1 and 2 are quite clear, we go straight to steps 3, namely code the program in C++A simple C++ program continued#include <iostream.h>int main ( ){ cout << “Hello World!” << endl; return 0;}Another simple program. What does it do?#include <iostream.h>int main ( ){ double x, y, z, avg; cout << “Enter 3 values: “; cin >> x >> y >> z; avg = ( x + y + z ) / 3; cout << “The average of three arbitrary values is “ << avg; return 0;}C++ language elements (tokens)•Keywords: 62 reserved word including return; each has special meaning and must not be misspelled. •Identifier: names chosen by the programmer; it is usually used to name or identify a memory location (known as a variable) or a function.•Operators: specifies operations•Constants: may be numeric or non-numeric•Punctuation symbols such as ;.Tokenize the above programsIn the two programs•What are the keywords?•What are the identifiers?•What are the punctuators?•What are the constants?•What are the operators?Question?•What does #include <iostream.h> mean?•What are the rest of the lines in the program for?•Why return 0?•What are cin and cout?•What is >>?•What is <<?•Are the ordering of lines (instructions) in the program important?•Can one use u, v, and w in place of x, y, and z?Divide and conquer: a modular approach to a complex