Search results
Results from the WOW.Com Content Network
C struct data types may end with a flexible array member [1] with no specified size: struct vectord { short len ; // there must be at least one other data member double arr []; // the flexible array member must be last // The compiler may reserve extra padding space here, like it can between struct members };
In C and C++ arrays do not support the size function, so programmers often have to declare separate variable to hold the size, and pass it to procedures as a separate parameter. Elements of a newly created array may have undefined values (as in C), or may be defined to have a specific "default" value such as 0 or a null pointer (as in Java).
If an array has unknown size (i.e. the array was an incomplete type), the number of initializers determines the size of the array and its type becomes complete: int x [] = { 0 , 1 , 2 } ; Compound designators can be used to provide explicit initialization when unadorned initializer lists might be misunderstood.
size_t is an unsigned integer type used to represent the size of any object (including arrays) in the particular implementation. The operator sizeof yields a value of the type size_t . The maximum size of size_t is provided via SIZE_MAX , a macro constant which is defined in the < stdint.h > header ( cstdint header in C++).
In computer science, an opaque data type is a data type whose concrete data structure is not defined in an interface.This enforces information hiding, since its values can only be manipulated by calling subroutines that have access to the missing information.
A basic example is in the argv argument to the main function in C (and C++), which is given in the prototype as char **argv—this is because the variable argv itself is a pointer to an array of strings (an array of arrays), so *argv is a pointer to the 0th string (by convention the name of the program), and **argv is the 0th character of the ...
C++ generally prohibits forward references, but they are allowed in the special case of class members. Since the member function accessor cannot be compiled until the compiler knows the type of the member variable myValue , it is the compiler's responsibility to remember the definition of accessor until it sees myValue 's declaration.
In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also supported.