Search results
Results from the WOW.Com Content Network
In the C++ programming language, a reference is a simple reference datatype that is less powerful but safer than the pointer type inherited from C.The name C++ reference may cause confusion, as in computer science a reference is a general concept datatype, with pointers and C++ references being specific reference datatype implementations.
Many languages have explicit pointers or references. Reference types differ from these in that the entities they refer to are always accessed via references; for example, whereas in C++ it's possible to have either a std:: string and a std:: string *, where the former is a mutable string and the latter is an explicit pointer to a mutable string (unless it's a null pointer), in Java it is only ...
array[i] means element number i, 0-based, of array which is translated into *(array + i). The last example is how to access the contents of array. Breaking it down: array + i is the memory location of the (i) th element of array, starting at i=0; *(array + i) takes that memory address and dereferences it to access the value.
A reference is an abstract data type and may be implemented in many ways. Typically, a reference refers to data stored in memory on a given system, and its internal value is the memory address of the data, i.e. a reference is implemented as a pointer. For this reason a reference is often said to "point to" the data.
The dope vector is a complete handle for the array, and is a convenient way to pass arrays as arguments to procedures. Many useful array slicing operations (such as selecting a sub-array, swapping indices, or reversing the direction of the indices) can be performed very efficiently by manipulating the dope vector. [2]
In C# and Java, variadic arguments are simply collected in an array. Caller can explicitly pass in an array in place of the variadic arguments. This can only be done for a variadic parameter. It is not possible to apply an array of arguments to non-variadic parameter without using reflection.
A tracking reference in C++/CLI is a handle of a passed-by-reference variable. It is similar in concept to using *& (reference to a pointer) in standard C++, and (in function declarations) corresponds to the ref keyword applied to types in C#, or ByRef in Visual Basic .NET. C++/CLI uses a ^% syntax to indicate a tracking reference to a handle.
Data layout is critical for correctly passing arrays between programs written in different programming languages. It is also important for performance when traversing an array because modern CPUs process sequential data more efficiently than nonsequential data. This is primarily due to CPU caching which exploits spatial locality of reference. [1]