Four explicit data-type conversion functions in C + +

1 reinterpret_cast (conversion is implemented during compilation)

The Reinterpret_cast type conversion function converts a pointer of one type into a pointer to another type. This conversion is not used to modify the format in which the value data of a pointer variable is stored (without changing the value of the pointer variable) and can be done simply by interpreting the type of the pointer during compilation.

Reinterpret_cast can convert a pointer value to an integer number. However, it cannot be used for conversions that are not pointer types, otherwise they will not be compiled.

When to use reinterpret_cast for data type conversions:

(1) Converts the base type pointer to a pointer of another type.

For example:

Conversion of the base type pointer

double d = 9.3；
double *pd = &d；
int *pi = reinterpret_cast<int *>（pd）；//相当于隐式转换int * pi = （int *）pd；

(2) Converts a pointer to a class to a pointer to another class.

Conversion of class pointer type:

class A{}；
class B{}；
A* pa = new A；
B* = reinterpret_ cast<B*>pa；

(3) Non-pointer type cannot be converted

For example:

converting an int type to a float type cannot be converted to a successful

int i = 8;

Double dl = reinterpret_cast<double> (i);

(4) cannot convert a const pointer to a pointer of type void*

Const int* PCI = 0;

void *PV = reinterpret_cast<void*> (PCI);