虽然p1与&q都是unqualified的,但p1指向的对象类型为pointer to const int,&q指向的类型为pointer to int,如前所述,两者是不相容类型,不符合两操作数必须指向相容类型的规定,因此赋值非法。 根据上述规则,一个pointer to const T不能赋予pointer to T,但是,一个const pointer却能赋予non-cons
3. 把一个const对象的地址赋给一个普通的,指向非const对象的指针会导致编译错误 constdoublepi =3.14;double*ptr = π//error: ptr is a plain pointerconstdouble*cptr = π//ok: cptr is a pointer to const 4 不能使用void *指针保存const对象的地址,而必须使用const void *类型的指针保存const对象的...
int const* is pointer to constant integer. This means that the variable being declared is a pointer, pointing to a constant integer. Effectively, this implies that the pointer is pointing to a value that shouldn't be changed. What is a constant char? const char* is a mutable pointer to ...
// constant_values4.cpp#include<stdio.h>intmain(){constchar*mybuf ="test";char*yourbuf ="test2"; printf_s("%s\n", mybuf);constchar*bptr = mybuf;// Pointer to constant dataprintf_s("%s\n", bptr);// *bptr = 'a'; // Error} ...
// x is just a read-only pointer to something that may or may not be a constantvoidconstFunc(constint *x){// local_var is a true constantconstint local_var = 42;// Definitely undefined behaviour by C rules doubleIt((int*)&local_var);// Who knows if this is UB? doubleIt((...
The constant pointer to a variable is useful where you want a storage that can be changed in value but not moved in memory. Because the pointer will always point to the same memory location, because it is defined with const keyword, but the value at that memory location can...
(Unfortunately, the far and near keywords don’t follow this rule, since they were modeled after Microsoft’s keyword usage.) The const keyword also modifies the token to its left. Thus, “char const * pcc” indicates that pcc is a pointer to a constant char. The pointer itself is not...
// const_pointer.cppint*constcpObject =0;int*pObject;intmain(){ pObject = cpObject; cpObject = pObject;// C3892} The following sample shows how to declare an object as const if you have a pointer to a pointer to an object.
pointer constant_ptr may be clarified by including a definition for the type ‘pointer to int’....
int * const 2. => const pointer to int so the pointer "points" to an int that can be changed, but the pointer can't changeconst int * const 1. => int const * const 2. => const pointer to const int constant pointer (can't change) points to an int that you can't change...