Chapter 2 – Getting Started

1. Chapter 2 –Getting Started

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

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

4. starts comment ends comment 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 */ Lesson 2.2

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

6. 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

7. 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

8. 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

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

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

11. 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

12. 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

13. 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” ; }

14. 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