#SIZE OF A POINTER CODE#

The latter is a type name enclosed in parentheses. The operand is written following the keyword sizeof and may be the symbol of a storage space, e.g., a variable, an expression, or a type cast.

#SIZE OF A POINTER CODE#

The operator sizeof produces the required memory storage space of its operand when the code is compiled. Int *pointer = malloc(10 * sizeof *pointer) The use of sizeof enhances readability, since it avoids unnamed numeric constants ( magic numbers).ДЄn equivalent syntax for allocating the same array space results from using the dereferenced form of the pointer to the storage address, this time applying the operator to a pointer variable: In addition, it is frequently difficult to predict the sizes of compound datatypes such as a struct or union, due to padding. The exception to this is the data type char, which always has the size 1 in any standards-compliant C implementation. For example, even though most implementations of C and C++ on 32-bit systems define type int to be four octets, this size may change when code is ported to a different system, breaking the code. It is generally not safe to assume the size of any datatype. The size of the block allocated is equal to the number of bytes for a single object of type int multiplied by 10, providing space for ten integers. In this example, function malloc allocates memory and returns a pointer to the memory block. Int *pointer = malloc(10 * sizeof (int))

For example, runtime allocation of array space may use the following code, in which the sizeof operator is applied to the cast of the type int: Though for any given implementation of C or C++ the size of a particular datatype is constant, the sizes of even primitive types in C and C++ may be defined differently for different platforms of implementation. Many programs must know the storage size of a particular datatype.

Size of a pointer