C++中const

#include<iostream> 
using namespace std;
struct Teacher
{
	char name[10];
	int age;
};
//指针所指向的内存空间，不能修改 
int operatorTeacher01(const Teacher *pT) 
{	
//	pT—>age=10; 
	return 0;
}
//指针变量本身，不能修改 
int operatorTeacher02( Teacher * const pT) 
{	
	//pT—>age=10; 
	//pT=NULL;
	return 0;
}

int operatorTeacher03( const Teacher * const pT) 
{	
	//pT—>age=10; 
	//pT=NULL;
	printf("%d\n",pT->age);
	return 0;
}

int main(){
//	const int a;
//	int const b;//与上相同 
//	const int *c;//const修饰的是指针所指向的内存空间，不能被修改 
//	int* const d;// 
//	const int *const e;
	cout<<"hello..."<<endl;
	Teacher t1;
	t1.age=33;
	operatorTeacher03(&t1);
	system("pause");
}

1.const是定义常量，意味着只读 

#include<iostream> 
using namespace std;
int main()
{
	const int a=10;
	int*p=NULL;
	p=(int*)&a;
	*p=20;
	printf("a:%d\n",a);
	system("pause");
}