Software Engineers Handbook/Language Dictionary/C++

C++ C++ is an Multi-paradigmed programming language derived from C. Type C++ is a full, Multi-paradigmed programming language implementing the following paradigmen: generic (template metaprogramming), imperative and object-oriented (class-based) Execution Entry Point An executable starts with the main() method. General Syntax The typical statement is completed by a semi-colon. For the assignment of b to a use: a = b; Comments // this is an inline comment. Everything after the // is a comment. Block comments are specified by a starting /* and ending */ They can span multiple lines. /* * this is a block comment */ Variable Declarations Declarations can appear anywhere in the implementation. Declare i as an integer: int i; Here are two ways to declare i as an integer and give it an initial value of 0: int i = 0; int i(0); Method Declaration/Implementation Methods are declared by specifying the interface for the method. It is often declared within the scope of a class. return_type function_name(argument_1_type arg_1_name, argument_2_type arg_2_name, default_argument_type default_arg_name = default_arg_value); Method implementation repeats much of the same information return_type class_name::function_name(argument_1_type arg_1_name, argument_2_type arg_2_name, default_argument_type default_arg_name) { // work with arg_1_name, arg_2_name, and default_arg_name // depending on the argument types the variables are passed by // value, reference, or are constant // don't forget to return something of the return type return 36; } IMPORTANT POINT A beginner in C/C++ might get confused about the distinction between how pointers are declared in a function prototype vs. how the function is defined. For example, if my_function does not return anything, but accepts one floating point input, its function prototype looks as follows: void my_function(float *some_variable); However, if the variable my_var is defined to be a pointer to a float, for example: float *my_var; Then the manner in which my_function is invoked is as follows: my_function(my_var); Beginners sometimes get confused about the fact that a "*" is used to tell the compiler in a prototype statement that a variable is a pointer, but a "*" is not syntactically used during invocation of a function that accepts a pointer as input. Scope Scope is defined by curly braces. { // this the beginning of a scope // the scope is about to end } Conditional Statements If and only if A is equal to B assign C to D, otherwise, assign E to F. if( A == B ) { D = C; // more code can be added here. It is used if and only if A is equal to B } else { F = E; // more code can be added here. It is used if and only if A is not equal to B } or if( A == B ) D = C; //more lines of code are not permitted after this statement else F = E; Alternatively, a switch statement can be used for multiple choice operations. This sample converts a number input to text. switch( number_value ) { case 37: text = "thirty-seven"; break; // this line prevents the program from writing over this value with the // following code case 23: text = "twenty-three"; break; default: // this is used if none of the previous cases contain the value text = "unknown number"; } Looping Statements This code counts from 0 to 9, adding up the contents of the array. int i = 0; for( int index = 0; index < 10; index = index + 1 ) { i = array[index]; } This code repeats until the number 4 is found. If this runs off of the end of the array, there could be a problem. int index = 0; while( 4 != array[index] ) { index = index + 1; } This code increments the counter before the check is made, so that it starts with element 1. int index = 0; do { index = index + 1; } while( 4 != array[index] ); Output Statements printf( "%s","Hello world!\n" ); or std::cout << "Hello world!" << std::endl; Containers The standard template library has a variety of containers including vector, bit-set, list, map and multi-set. Algorithms The standard template library has a variety of algorithms including sort, remove_if, and find_if. Garbage collection Garbage collection is manual. Physical Structure Generally the interfaces are defined in header files, often *.h. The implementation files are often named *.cpp. Useful collections of classes can be compiled into libraries, often *.dll, *.a, or *.so, which can be compiled into executables (statically linked) or used on the fly (dynamically linked). Tips Don't confuse these two: = // assignment == // comparison, is equal to Often using the one you don't want will compile, and will produce results you did not expect. A good practice is to write; if(CONSTANT == variable) rather than if(variable == CONSTANT) since the compiler will catch; if(CONSTANT = variable) but not if(variable = CONSTANT). Arrays start with index 0. Web References C++ wikibooks Books and Articles Bruce Eckel, Thinking in C++, Volume 1: Introduction to Standard C++ 0139798099. It has helped many people make the leap from C to C++. It is available for free online at Bruce Eckel's site. Nicolai M. Josuttis, The C++ Standard Library : A Tutorial and Reference 0201379260. It contains lengthy and advanced discussions on the standard template library conatiners and algorithms. Stanley B. Lippman, Josée Lajoie & Barbara E. Moo, C++ Primer 0321714113. This is a very thorough introduction to C++, taking nearly 1000 pages to introduce programmers to C++. Andrew Koenig & Barbara E. Moo, Accelerated C++ 020170353X. This is another introduction to C++, but stresses the use of the STL. It is a quite compact introduction, with a steeper learning curve better suited for those who already know another programming language. Scott Meyers, Effective C++ 0321334876, More Effective C++ 020163371X, Effective STL 0201749629. Meyers' series of books contain the best C++ practices, from class design to minimising compilation dependencies. Herbert Schildt, C++: The Complete Reference 0072226803. It contains dictionary-like listings of code syntax and usage. The structure does not make it useful to learn the language from scratch. However, it could be very useful when switching from a similar language. Bjarne Stroustrup, The C++ Programming Language 0201889544. Written by the creator of C++, it covers everything from the core language to the standard library. The book itself has over 1300 pages. deep