STRUCTURED PROGRAMMING Complete C++ Program

Content 2  Main Function  Preprocessor directives  User comments  Escape characters  cout statement  String literals  C++ keywords  General C++ syntax rules

Objectives 3  By the end you should be able to:  Identify the main function, Preprocessor directives, and user comments in a C++ program  Recognize some of the C++ keywords  Apply C++ syntax rules in producing output messages using cout stream and iostream library  Use Escape characters properly in a cout statement

Complete Program 4 commentsstatement main function preprocessor directive braces string literal output on screen

C++ Program Structure  Comments: remarks that are ignored by the compiler  Compiler directives: commands for compiler, which are needed to compile and run program effectively  Main function: where every program begins  Braces: mark the beginning and ending code blocks  Statement: a line of C++ code 5

Comments  Explain programs, their purpose, authors names and future modification notes to other programmers  Improve program readability  Ignored by compiler  Single-line comment  Begin with //  Multi-line comment  Start with /*  End with */ 6 // Fig. 2.1: fig02_01.cpp // Text-printing program /* Fig. 2.1: fig02_01.cpp Text-printing program */ // Fig. 2.1: fig02_01.cpp // Text-printing program /* Fig. 2.1: fig02_01.cpp Text-printing program */

Preprocessor Directives  Instructions to the compiler rather than part of C++ language  Processed by preprocessor before compilation  Tells preprocessor to include the input/output stream header file  Begin with #  It tells the compiler to put code from iostream into the program before actually creating the executable  Forgetting to include the file will result in a compilation error 7 #include name of header file

main Function  Block of codes carries out a specific task  Part of every C++ program  ONLY one function in a program must be main  Can or can’t be “return” a value  Returns an integer; once return  Body is delimited by braces { }  return statement  The value 0 indicates the program terminated successfully 8 int main() { return 0; } int main() { return 0; }

Using cout  Namespace  std:: Specifies using a name that belongs to “namespace” std Can be removed through use of using statements  Standard output stream object  std::cout “Connected” to screen Defined in input/output stream header file 9

Using cout (cont.)  Stream insertion operator <<  Value to right (right operand) inserted into left operand  Example std::cout << "Hello"; Inserts the string "Hello" into the standard output then displays to the screen  Escape characters  A character preceded by "\" Indicates “special” character output  Example "\n“  Cursor moves to beginning of next line on the screen 10

Escape Sequences 11

Modifying First Program Multiple stream insertion statements produce one line of output

Modifying First Program Use newline characters to print on multiple lines

Syntax Rules 14  Must include for cout to work properly  You must use the namespace std for cout to work properly  C++ is case sensitive  Make sure you don’t capitalize any of the letters in C++ keywords  Every statement ends with a statement terminator ( ; )  except for function header, function braces and preprocessor directives  String literals must be enclosed in “ ”  Main function must return a value to the OS  Every opening brace { must have an enclosing brace }

Exercise Write a program that display your name, ID, and section in our course. Then, save the source code file as yourName.cpp

Exercise Write a program that print the message of your choice to the screen. Make the message at least four lines long. Save the source file as myMessage.cpp

Included Sections 17 Chapter 2: from section 1 to 3