C++ Examples (ANSI/ISO Standard Version)

Copyright C. S. Tritt, Ph.D.

Linked are four C++ programs that illustrate some of the major features of the language. For more information on many of these language features, see my C++ Quick Reference Page.

Some of these examples use function prototypes and put function definitions after main(). An alternate approach is to skip the function prototyhpes and put function definitions before main(). The prototype approach scales up better, while the functions before main() approach is more convenient for small programs.

sum.cpp	swap.cpp
stdlib.cpp	arrays.cpp
strings.cpp	complex.cpp
comments.cpp	cppstrings.html
cstrings.cpp	cstrings2.cpp
stlstrings.cpp	stlstrings2.cpp
stringswitch.cpp	polytropic.cpp
formatedio.cpp	rectangle.cpp

The program sum.cpp illustrates:

• Overall program structure including function declaration with default values.
• Inclusion of header files.
• Declaration of variables of built in types.
• Output formating.
• Writing to the screen (console output, i.e. cout) << (the stream insertion operator).
• Reading from the keyboard (console in, i.e. cin) >> (the stream extraction operator).
• Simple selection structures (if statements).
• Use of functions that return values but don't change their arguments.

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The program swap.cpp illustrates:

• Declaration of variables of built in types with initialization.
• File I/O using streams.
• Use of functions that change the values of their arguments using references.
• Use of the assignment operator (=).

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The program stdlib.cpp illustrates:

• Using command line arguments.
• Using compiler directives and conditional compilation.
• Using the assert() mechanism for error handling.
• Getting the system time and using it to seed a random number generator.
• Random number generation with srand(int seed) and rand functions.
• Improving a poor random number generator.
• System calls with the system(char* command) function.

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The program arrays.cpp reads from file asum.in and illustrates:

• Use of const (constant) values.
• Creation of vectors.
• Passing vectors as function arguments.
• Reading from files of unknown size (monitoring istream status).
• Repetitive structures (while and for loops).
• The increment operators (++).
• Selection structures (if-else statements).
• Use of the .size, .empty, .begin, .insert, .erase, .resize, .clear and .swap vector class member functions.

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The program strings.cpp illustrates:

• Creation of strings.
• Concatenation of strings.
• Use of the .insert, .find, .length and .substr string class member functions.

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The program complex.cpp reads from file complex.dat and illustrates:

• Declaration and definition of classes and user defined types.
• Declaration, definition and use of member functions.
• Creating objects.
• Using member functions.
• Function overloading.
• The char built-in type.
• Skipping comments in data files.
• Use of standard library math functions declared in cmath.

Note: Modern C++ has a complex template class (defined in <complex>).

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The program comments.cpp reads text from the file sometext.txt and illustrates:

• How to look ahead (peek) while reading from a file (ifstream).
• How to selectively skip data (comments) in a file (ifstream).
• How to extract multi-word text from a stream into an STL string using getline().
• How to extract data from files of arbitary length.

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The web page cppstrings.html discusses various ways in which to handle textual data in modern C++.

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The program cstrings.cpp illustrates:

• A way to use C strings.
• A way to get and respond to textual input from a user.
• How to use constants to support multiple languages in program.

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The program cstrings2.cpp illustrates:

• Another way to use C strings.
• Another way to get and respond to textual input from a user.
• How to use the strcmp() function to compare C stings.

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The program stlstrings.cpp illustrates:

• A way to use STL strings.
• A way to get and respond to textual input from a user.
• How to compare characters within STL strings.

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The program stlstrings2.cpp illustrates:

• Another way to use STL strings.
• Another way to get and respond to textual input from a user.
• How to use the STL string comparison operators (i.e., ==).

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The program stringswitch.cpp illustrates:

• Yet another way to use STL strings.
• Yet another way to get and respond to textual input from a user.
• The use of the switch control construct.
• The use of the [] STL string operator.

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The program polytropic.cppreads data from the file ideal.dat and illustrates:

• How to use C++ objects to solve a simple thermodynamics problem.
• How to place constants in objects.
• How to declare and define classes.
• How to create objects.
• How to selectively skip comments in data files.
• How to extract data from files of arbitary length.

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The program formatedio.cpp illustrates:

• Use of formated stream output.

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The program rectangle.cpp illustrates:

• Using Horstmann's graphics classes.
• Getting mouse input.

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Among the "advanced" C++ topics not covered in these examples are:

• Type conversion and casting.
• Multidimensional arrays.
• Loop interruption statements (break and continue).
• Separate compilation of multiple source files and use of non-standard libraries.
• Pointers and dynamic memory management (new and delete).
• User defined destructors.
• I/O redirection in DOS and UNIX.
• Bitwise operations.
• Operator overloading.
• Exception handling (try-catch blocks), but assert() is illustrated.
• Advanced object oriented design.
• Use of the Standard Template Library (STL) beyond the use of the string and vector classes.
• Windows programming using C++ beyond using simple graphics libraries.