C++ 的类型转换详解

static_cast<目标类型> (标识符)

int a = 10;
int b = 3;
cout<<static_cast<float>(a)/b<<endl; //float = int int = float
return 0;

int *p; void *q;
p = static_cast<int*>(q);

char *p = static_cast<char*>(malloc(100));

reinterpret_cast<目标类型> (标识符)

#include <iostream>
#include <string.h>
using namespace std;
int main()
{
	int x = 0x12345648;
	char *p = reinterpret_cast<char*>(&x);
	//char*p = static_cast<char*>(&x); error
	printf("%x\n",*p);
	int a[5] = {1,2,3,4,5};
	int *q = reinterpret_cast<int*>(a+1);
	printf("%x\n",*q);
	return 0;
}

const_cast<目标类型> (标识符) //目标类类型只能是指针或引用。

#include <iostream>
using namespace std;
void func(int & ref) //别人己经写好的程序或类库
{
	cout<<ref<<endl;
}
int main(void)
{
	const int m = 1;
	func(const_cast<int&>(m));
	return 0;
}

#include <iostream>
using namespace std;
int main()
{
	const int x = 200;
	int & a =const_cast<int&>(x); // int &a = x;
	a = 300;
	cout<<a<<x<<endl;
	cout<<&a<<"---"<<&x<<endl;
	int *p =const_cast<int*>(&x); // int *p = &x;
	*p = 400;
	cout<<a<<*p<<endl;
	cout<<p<<"---"<<&x<<endl;
	struct A
	{
		int data;
	};
	const A xx = {1111};
	A &a1 = const_cast< A&>(xx);
	a1.data = 222;
	cout<<a1.data<<xx.data<<endl;
	A *p1 = const_cast<A*>(&xx);
	p1->data = 333;
	cout<<p1->data<<xx.data<<endl;
	return 0;
}

dynamic_cast<目标类型> (标识符)