Pointer to the const object

If the pointer points to a const object, you cannot use the pointer to change the const value. To ensure this feature, the C ++ language requires that the pointer to the const object must also have the const feature.

Therefore, assigning the address of a const object to a common const object causes non-const object pointers to cause compilation errors:

Const double Pi = 3.14;

Double * PTR = & PI; // Error

Const double * cptr = & PI; // OK

You cannot use the void * pointer to save the address of the const object. Instead, you must use the const void * pointer to save the address of the const object:

Assign the address of a non-const object to the pointer to the const object. However, any attempt to use the const object pointer to repair this non-const object will result in a compilation error. Once defined, the const Object Pointer cannot be used to modify the value of the object. But it does not indicate that this non-const object cannot be modified.

If the object pointed to by the const pointer is not const, you can directly assign a value to the object or indirectly use a common non-const pointer to modify its value: after all, this value is not Const.

# Include <iostream> using namespace STD; void main () {char STR [] = "hello"; const char * P = STR; STR [0] = 'X '; // P [0] = 'X'; // cout <STR <Endl; cout <* P <Endl; cout <p [0] <Endl; cout <p <Endl ;}

In vc6.0

Char * P = "hello ";

Such statements can be run. P points to a String constant, but the pointer P is not defined as a const object. However, the default pointer P is a pointer to a const object. The pointer P cannot be used to modify a String constant or a String constant. (Only for the vc6.0 compiler, because different compilers have different storage and processing methods for string constants, such as P [0] = 'X'; statements may run in tc2.0. Since different compilers support different string constants, it is best not to modify string constants)

My personal summary: Welcome to shoot bricks!