将指针传递给函数时,这些形式的const很有用。函数参数应声明为最严格的const指针,以确保函数不会修改指针指向的值。这让函数更容易维护,在时过境迁和人员更换尤其如此。 void CalcArea(const double* const pPi, //const pointer to const data const double* const pRadius, //i.e.. nothing can be changed ...
将指针传递给函数时,这些形式的const很有用。函数参数应声明为最严格的const指针,以确保函数不会修改指针指向的值。这让函数更容易维护,在时过境迁和人员更换尤其如此。 void CalcArea(const double* const pPi, //const pointer to const data const double* const pRadius, //i.e.. nothing can be changed ...
对应的英文是倒过来的 pointer to const。 指针常量,就是指针的常量,指针本身为常量,指向不可更改。对应的英文是倒过来的 const pointer。 用英文理解会更简单一点。 英文记忆法 将程序由后往前念 将* 替换成自然语言 pointer to 将变量后面加上 is a const int p = 3; // p is a int const // 例如...
// 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} ...
// 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} ...
类似于上述第三节常量引用,指向常量的指针(pointer to const)不能改变其所指向的对象的值。通常使用const修饰符放在指针类型前来表示,如下所示: constintsize=128;constint*size_ptr=&size;//定义一个指向常量对象的指针*size_ptr=256;//错误,不允许修改 ...
// 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} ...
A const member function can modify the value of an object that is mutable or accessed through a pointer member. A common use is to maintain a cache rather than repeatedly do a complicated computation. For example, here is a Date that caches (memoizes) its string representation to simplify ...
Pointer to a const variable This means that the pointer is pointing to a const variable. const int* u; 1. Here, u is a pointer that can point to a const int type variable. We can also write it like, ...
const char * const p = greeting;//const pointer,const data 1. 2. 3. 4. 5. const出现在星号左边,表示被指物是常量;如果出现在星号右边,表示指针自身是常量;如果出现在两边,表示被指物和指针两者都是常量。 注意:如果被指物是常量,可以将const写在类型之前,或者在类型之后、星号之前。两种写法意义相同,...