Chapter 2 Introduction to C++

Chapter 2Introduction to C++ Namiq Sultan University of Duhok Department of Electrical and Computer Engineerin Reference: Starting Out with C++, Tony Gaddis, 2nd Ed. C++ Programming, Namiq Sultan

2.1 The Parts of a C++ Program • C++ programs have parts and components that serve specific purposes. C++ Programming, Namiq Sultan

Program 2-1 //A simple C++ program #include <iostream> using namespace std; int main () { cout<< “Programming is great fun!”; return 0; } Program Output: Programming is great fun! C++ Programming, Namiq Sultan

Table 2-1 Special Characters C++ Programming, Namiq Sultan

2.2 The cout Object • Use the cout object to display information on the computer’s screen. • The cout object is referred to as the standard output object. • Its job is to output information using the standard output device C++ Programming, Namiq Sultan

Program 2-2 // A simple C++ program #include <iostream> using namespace std; int main () { cout << “Programming is “ << “great fun!”; return 0; } Output: Programming is great fun! C++ Programming, Namiq Sultan

Program 2-3 // A simple C++ program #include <iostream> using namespace std; int main () { cout<< “Programming is “; cout << “ great fun!”; return 0; } Output: Programming is great fun! C++ Programming, Namiq Sultan

Program 2-4 // An unruly printing program #include <iostream> using namespace std; int main() { cout << "The following items were top sellers"; cout << "during the month of June:"; cout << "Computer games"; cout << "Coffee"; cout << "Aspirin"; return 0; } Program Output The following items were top sellersduring the month ofJune:Computer gamesCoffeeAspirin C++ Programming, Namiq Sultan

New lines • cout does not produce a newline at the end of a statement • To produce a newline, use either the stream manipulator endl • or the escape sequence \n C++ Programming, Namiq Sultan

Program 2-5 // A well-adjusted printing program #include <iostream> using namespace std; int main() { cout << "The following items were top sellers" << endl; cout << "during the month of June:" << endl; cout << "Computer games" << endl; cout << "Coffee" << endl; cout << "Aspirin" << endl; return 0; } C++ Programming, Namiq Sultan

Program Output The following items were top sellers during the month of June: Computer games Coffee Aspirin C++ Programming, Namiq Sultan

Program 2-6 // Another well-adjusted printing program #include <iostream> using namespace std; int main() { cout << "The following items were top sellers" << endl; cout << "during the month of June:" << endl; cout << "Computer games" << endl << "Coffee"; cout << endl << "Aspirin" << endl; return 0; } C++ Programming, Namiq Sultan

Program 2-7 // Yet another well-adjusted printing program #include <iostream> using namespace std; int main() { cout << "The following items were top sellers\n"; cout << "during the month of June:\n"; cout << "Computer games\nCoffee"; cout << "\nAspirin\n"; return 0; } C++ Programming, Namiq Sultan

Table 2-2 C++ Programming, Namiq Sultan

2.3 The #include Directive • The #include directive causes the contents of another file to be inserted into the program • Preprocessor directives are not C++ statements and do not require semicolons at the end C++ Programming, Namiq Sultan

2.4 Variables and Constants • Variables represent storage locations in the computer’s memory. Constants are data items whose values do not change while the program is running. • Every variable must have a declaration. C++ Programming, Namiq Sultan

Program 2-8 #include <iostream> using namespace std; int main() { int value; value = 5; cout << “The value is “ << value << endl; return 0; } Program Output: The value is 5 C++ Programming, Namiq Sultan

Assignment statements: Value = 5; //This line is an assignment statement. • The assignment statement evaluates the expression on the right of the equal sign then stores it into the variable named on the left of the equal sign • The data type of the variable was in integer, so the data type of the expression on the right should evaluate to an integer as well. C++ Programming, Namiq Sultan

Constants • A variable is called a “variable” because its value may be changed. A constant, on the other hand, is a data item whose value does not change during the program’s execution. C++ Programming, Namiq Sultan

2.5 Identifiers • Must not be a keyword • The first character must be a letter or an underscore • The remaining may be letters, digits, or underscores • Upper and lower case letters are distinct C++ Programming, Namiq Sultan

Table 2-3 The C++ Keywords Asm auto bool break case catch char class const const_cast continue default delete do double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new operator private protected public register reinterpret_cast return short signed sizeof static static_cast struct switch template this throw true try typedef typeid Type name union unsigned using virtual void volatile wchar_t while C++ Programming, Namiq Sultan

Table 2-4 Some Variable Names C++ Programming, Namiq Sultan

2.6 Integer Data Types • There are many different types of data. Variables are classified according to their data type, which determines the kind of information that may be stored in them. • Integer variables only hold whole numbers. C++ Programming, Namiq Sultan

Program 2-12 // This program shows three variables declared on the same line. #include <iostream> using namespace std; int main() { int floors, rooms, suites; floors = 15; rooms = 300; suites = 30; cout << "The Grande Hotel has " << floors << " floors\n"; cout << "with " << rooms << " rooms and " << suites; cout << " suites.\n"; return 0; } C++ Programming, Namiq Sultan

Program Output The Grande Hotel has 15 floors with 300 rooms and 30 suites. C++ Programming, Namiq Sultan

2.7 The char Data Type • Usually 1 byte long • Internally stored as an integer • ASCII character set shows integer representation for each character • ‘A’ == 65, ‘B’ == 66, ‘C’ == 67, etc. • Single quotes denote a character, double quotes denote a string C++ Programming, Namiq Sultan

Program 2-14 // This program uses character constants #include <iostream> using namespace std; int main() { char letter; letter = 'A'; cout << letter << endl; letter = 'B'; cout << letter << endl; return 0; } C++ Programming, Namiq Sultan

Program Output A B C++ Programming, Namiq Sultan

Strings • Strings are consecutive sequences of characters and can occupy several bytes of memory. • Strings always have a null terminator at the end. This marks the end of the string. • Escape sequences are always stored internally as a single character. C++ Programming, Namiq Sultan

Let’s look at an example of how a string is stored in memory. • "Sebastian" would be stored. • ‘A’ is stored as • “A” is stored as S e b a s t i a n \0 65 65 0 C++ Programming, Namiq Sultan

Review key points regarding characters, and strings: • Printable characters are internally represented by numeric codes. Most computers use ASCII codes for this purpose. • Characters occupy a single byte of memory. • Strings are consecutive sequences of characters and can occupy several bytes of memory. • Strings always have a null terminator at the end. This marks the end of the string. • Character constants are always enclosed in single quotation marks. • String constants are always enclosed in double quotation marks. • Escape sequences are always stored internally as a single character. C++ Programming, Namiq Sultan

2.8 Floating Point Data Types • Floating point data types are used to declare variables that can hold real numbers C++ Programming, Namiq Sultan

// This program uses floating point data types #include <iostream> using namespace std; int main() { float distance; float mass; distance = 1.495979; mass = 1.989; cout << "The Distanceis " << distance << " kilometers \n"; cout << "The mass is " << mass << " kilograms.\n"; return 0; } C++ Programming, Namiq Sultan

Program Output The Sun is 1.4959 kilometers The mass is 1.989 kilograms. C++ Programming, Namiq Sultan

2.9 The bool Data Type • Boolean variables are set to either true or false C++ Programming, Namiq Sultan

Program 2-17 #include <iostream> using namespace std; int main () { bool boolValue; boolValue = true; cout << boolValue << endl; boolValue = false; cout << boolValue << endl; return 0; } C++ Programming, Namiq Sultan

Program Output 1 0 Internally, true is represented as the number 1 and false is represented by the number 0. C++ Programming, Namiq Sultan

2.11 Variable Assignment and Initialization • An assignment operation assigns, or copies, a value into a variable. When a value is assigned to a variable as part of the variable’s declaration, it is called an initialization. C++ Programming, Namiq Sultan

Program 2-19 #include <iostream> using namespace std; int main () { int month = 2, days = 28; cout << “Month “ << month << “ has “ << days << “ days.\n”; return 0; } Program output: Month 2 has 28 days. C++ Programming, Namiq Sultan

2.13 Arithmetic Operators • There are many operators for manipulating numeric values and performing arithmetic operations. • Generally, there are 3 types of operators: unary, binary, and ternary. • Unary operators operate on one operand • Binary operators require two operands • Ternary operators need three operands ( ?: in ch 4) C++ Programming, Namiq Sultan

Table 2-8 C++ Programming, Namiq Sultan

Program 2-21 // This program calculates hourly wages. The variables are used as follows: // regWages: holds the calculated regular wages. // basePay: holds the base pay rate. // regHours: holds the number of hours worked less overtime. // otWages: holds the calculated overtime wages. // otPay: holds the payrate for overtime hours. // otHours: holds the number of overtime hours worked. // totalWages: holds the total wages. #include <iostream> using namespace std; int main() { float regWages, basePay = 18.25, regHours = 40.0; float otWages, otPay = 27.78, otHours = 10; float totalWages; C++ Programming, Namiq Sultan 44

Program 2-21 regWages = basePay * regHours; otWages = otPay * otHours; totalWages = regWages + otWages; cout << "Wages for this week are $" << totalWages << endl; return 0; } C++ Programming, Namiq Sultan

2.14 Comments • Comments are notes of explanation that document lines or sections of a program. • Comments are part of a program, but the compiler ignores them. They are intended for people who may be reading the source code. • Commenting the C++ Way // • Commenting the C Way /* */ C++ Programming, Namiq Sultan

Program 2-22 // PROGRAM: PAYROLL.CPP // Written by Herbert Dorfmann // This program calculates company payroll #include <iostream> using namespace std; int main(void) { float payRate; // holds the hourly pay rate float hours; // holds the hours worked int empNum; // holds the employee number (The remainder of this program is left out.) C++ Programming, Namiq Sultan

Program 2-24 /* PROGRAM: PAYROLL.CPP Written by Herbert Dorfmann This program calculates company payroll */ #include <iostream> using namespace std; int main(void) { float payRate; /* payRate holds hourly pay rate */ float hours; /* hours holds hours worked */ int empNum; /* empNum holds employee number */ (The remainder of this program is left out.) C++ Programming, Namiq Sultan

2.15 Programming Style • Program style refers to the way a programmer uses identifiers, spaces, tabs, blank lines, and punctuation characters to visually arrange a program’s source code. • Generally, C++ ignores white space. • Indent inside a set of braces. • Include a blank line after variable declarations. C++ Programming, Namiq Sultan

Program 2-26 #include <iostream> using namespace std; int main(){float shares=220.0; float avgPrice=14.67; cout <<"There were "<<shares<<" shares sold at $"<<avgPrice<<" per share.\n";return 0;} Program Output There were 220 shares sold at $14.67 per share. C++ Programming, Namiq Sultan

Chapter 2 Introduction to C++