Chapter 2 – Getting Started

Basic Program Structure #include <iostream> using namespace std; int main( ) { cout << “This is C++!”; } Header Location of header files Primary function Marks beginning of function body object insertion operator used to print to screen string – characters within double quotes semicolon: statement terminator C++ statement Marks end of function body Lesson 2.1

C++ Syntax Rules for writing statements Semicolon serve as statement terminator Case sensitivity Blank spaces Spacing Accepted modifications Lesson 2.1

Comments Notes in program describing what code does Perform no action in program Single line comment structure Begin with two slashes (no space between) // Line by itself or following statement Multiline comment structure Uses delimiters /* comments */ starts comment ends comment Lesson 2.2

Creating a Banner Set of comments at beginning of program name parameters used history author purpose date of program //*********************** // Name: Sally Student // Purpose: Assignment 2 // Date: 11/22/2003 // Reference: Chapter 2, #3 #include <iostream> . Lesson 2.2

Creating New Lines in Output Programmer must specify new line Line feeding \n in string constant cout << “\nwe can jump\n\ntwo lines.”; endl manipulator cout << endl<<“we can jump “; cout << endl<< endl <<“two lines.”; we can jump two lines. Lesson 2.3

Connecting Strings Can use backslash at end of line to indicate string constant to continue with next line cout << “This will \ continue on same line.” ; is equivalent to cout << “This will continue on same line.”; Lesson 2.3

Character Escape Sequences Other escape sequences exist for formatting Full listing in Table 2.1 Examples: \t horizontal tab \v vertical tab \% displays percent character \” displays double quote Lesson 2.3

Debugging Error in program called bug Process of looking for and correcting bugs Three types of errors Syntax Run-time Logic Lesson 2.4

Syntax Errors Mistakes by violating “grammar” rules Diagnosed by C++ compiler Must fix before compiler will translate code spelling cout coot << endl; int main ( ( ) mismatched parentheses Lesson 2.4

Run-Time Errors Violation of rules during execution of program Computer displays message during execution and execution is terminated Error message may help locating error Lesson 2.4

Logic Errors Computer does not recognize Difficult to find Execution is complete but output is incorrect Programmer checks for reasonable and correct output Lesson 2.4

Debugging Example #<include iostream> using namespace std; int main ( ); ( cout << ‘Hello world!’ cout << “Hello again”, endl; // Next line will output a name! ccut << “Sally Student”; /* Next line will output another name /* cout << John Senior; } # include <iostream> OK using namespace std; int main ( ) { cout << “Hello world!”; cout << “Hello again”<< endl; // Next line will output a name! cout << “Sally Student”; /* Next line will output another name */ cout << “John Senior” ; }

Summary Learned about: General program structure Rules of C++ syntax Creating comments and program banners Using escape sequences to format output Debugging programs Three types of errors: syntax, run-time, logic Chapter 2