To declare the object pointed to by the pointer asconstorvolatile, use a declaration of the form: C++ constchar*cpch;volatilechar*vpch; To declare the value of the pointer — that is, the actual address stored in the pointer — asconstorvolatile, use a declaration of the form: ...
result: not supported to pass pointer to const when you need to change content of var it pointed. Compile error: const_test.cpp: In function ‘voidChangeSize(constVar*)’: const_test.cpp:16:19: error: passing ‘constVar’as‘this’ argument of ‘voidVar::setSize(constint&)’ discards ...
double*ptr = π// const对象的地址不能赋给非const指针 constdouble*cptr = π// ok: cptr is a pointer to const constvoid*cpv = π// ok: cpv is const doubledval = 3.14; cptr = &dval;// ok: but can't change dval through cptr 可以通过赋值改变指针本身的值,但不能通过指针(eg:*p)...
int x{0}; const int* const cpci{&x}; // cpci is a const pointer to an integer treated as constant Copy This rule works for any of the simple cases covered in this lesson. Believe it or not, compound types can get more complex, and the right-to-left reading must be supplemented ...
When theconstvariable is initialized, it can not be assigned a different value during run-time. Thus, the third line in the following example’smainfunction is invalid, and the compiler won’t process it. Note that if you declare a pointer to the same type of a variable and then try to...
// basic_string_const_ptr.cpp // compile with: /EHsc #include <string> #include <iostream> int main( ) { using namespace std; basic_string<char>::const_pointer pstr1a = "In Here"; const char *cstr1c = "Out There"; cout << "The string pstr1a is: " << pstr1a << "." <...
// basic_string_const_ptr.cpp // compile with: /EHsc #include <string> #include <iostream> int main( ) { using namespace std; basic_string<char>::const_pointer pstr1a = "In Here"; const char *cstr1c = "Out There"; cout << "The string pstr1a is: " << pstr1a << "." <...
// 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} ...
const使用 声明一个常量 关键字const用来告诉编译器一个一旦被初始化过的变量就不能被修改 int a; ...
实际上,vbptr 指的是虚基类表指针(virtual base table pointer),该指针指向了一个虚基类表(virtual table),虚表中记录了虚基类与本类的偏移地址;通过偏移地址,这样就找到了虚基类成员,而虚继承也不用像普通多继承那样维持着公共基类(虚基类)的两份同样的拷贝,节省了存储空间。