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The motivation for inclusion of array was that it solves two problems of the C-style array: the lack of an STL-like interface, and an inability to be copied like any other object. It firstly appeared in C++ TR1 and later was incorporated into C++11 .
The C++ standard library instead provides a dynamic array (collection) that can be extended or reduced in its std::vector template class. The C++ standard does not specify any relation between new / delete and the C memory allocation routines, but new and delete are typically implemented as wrappers around malloc and free . [ 6 ]
In computer programming, initialization or initialisation is the assignment of an initial value for a data object or variable. The manner in which initialization is performed depends on the programming language , as well as the type, storage class, etc., of an object to be initialized.
The sizeof operator on such a struct gives the size of the structure as if the flexible array member were empty. This may include padding added to accommodate the flexible member; the compiler is also free to re-use such padding as part of the array itself.
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.
The lazy initialization technique allows us to do this in just O(m) operations, rather than spending O(m+n) operations to first initialize all array cells. The technique is simply to allocate a table V storing the pairs ( k i , v i ) in some arbitrary order, and to write for each i in the cell T [ k i ] the position in V where key k i is stored ...
Another array data type, intended for numerical use (especially to represent vectors and matrices); the C++ standard allows specific optimizations for this intended purpose. According to Josuttis, valarray was badly designed, by people "who left the [C++ standard] committee a long time before the standard was finished", and expression template ...
Array's destructor deletes the data array of the original, therefore, when it deleted copy's data, because they share the same pointer, it also deleted first's data. Line (2) now accesses invalid data and writes to it. This produces a segmentation fault. If we write our own copy constructor that performs a deep copy then this problem goes away.