Lecture Programming in C++ - Chapter 2: Getting started
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Chapter 2 –
Getting Started
Basic Program Structure
#include <iostream>
using namespace std;
int main( )
{
Header
Location of header files
Primary function
Marks beginning of function body
object
cout << “This is C++!”; string – characters within
C++ statement
double quotes
insertion operator used to print to screen
semicolon: statement terminator
}
Lesson 2.1
Marks end of function body
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
Lesson 2.2
//***********************
// Name: Sally Student
// Purpose: Assignment 2
// Date: 11/22/2003
// Reference: Chapter 2, #3
//***********************
#include <iostream>
.
.
.
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
\v
\%
\”
Lesson 2.3
horizontal tab
vertical tab
displays percent character
displays double quote
Debugging
Error in program called bug
Process of looking for and correcting bugs
Three types of errors
– Syntax
– Runtime
– 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 ( ()
Lesson 2.4
mismatched
parentheses
RunTime 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>
# include <iostream>
OK using namespace std;
using namespace std;
int main ( )
int main ( );
{
(
cout << “Hello world!”;
cout << ‘Hello world!’
cout << “Hello again”, endl; cout << “Hello again”<< endl;
// Next line will output a name!
// Next line will output
a name!
cout << “Sally Student”;
ccut << “Sally Student”;
/* Next line will
/* Next line will
output another name */
output another name /*
cout << “John Senior” ;
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, runtime, logic
Chapter 2
