typeid, const_cast<Type>的使用

 #include <bits/stdc++.h>
 using namespace std;

 class A {
     public :
         void Show() {
             cout << "A" << endl;
         }
 } ;

 class CC {
     public :
         void Show() {
             cout << "CC" << endl;
         }
 } ;

 class x {
     public :
         void Show() {
             cout << "x" << endl;
         }
 } ;

 class {
 } test;

 int main() {
     long long a, *b = ;
     int *c;
     double *d;
     cout << (typeid(a) == typeid(long long)) << endl;
     cout << (typeid(a) == typeid(double)) << endl;
     b = &a;
     cout << (typeid(*b) == typeid(long long)) << endl;
     cout << typeid(b).name() << endl;
     cout << typeid(*b).name() << endl;
     cout << typeid(c).name() << endl;
     cout << typeid(*c).name() << endl;
     cout << typeid(d).name() << endl;
     cout << typeid(*d).name() << endl;
     A t;
     cout << typeid(t).name() << endl;
     CC s;
     cout << typeid(s).name() << endl;
     x *p;
     cout << typeid(p).name() << ' ' << typeid(*p).name() << endl;
     class {
     } temp;
     cout << typeid(temp).name() << endl;
     cout << typeid(test).name() << endl;
     class {
     } temp2;
     cout << typeid(temp2).name() << endl;
     class a {
     } temp3;
     cout << typeid(temp3).name() << endl;
     cout << typeid(long).name() << endl;
     unsigned long long l;
     cout << typeid(l).name() << endl;
     short z;
     cout << typeid(z).name() << endl;
     return ;
 }

运行结果：

 Px
 x
 Pi
 i
 Pd
 d
 1A
 2CC
 P1x 1x
 Z4mainEUt_
 ._125
 Z4mainEUt0_
 Z4mainE1a
 l
 y
 s

 // 在ubuntu 13.10下的运行结果

const_cast<Type>去除const或volatile限制：

 #include <bits/stdc++.h>
 using namespace std;

 char *Test(const char *s) {
     char *t = const_cast<char *>(s);
     *t = 'z';
     return t;
 }

 int main() {
     const char *s1 = "abc";
     const char s2[] = "cba";
     //cout << Test(s1) << endl; // Run-Time Error
     cout << Test(s2) << endl;
     cout << s2 << endl;
     //cout << Test("ABC") << endl; // Run-Time Error
     return ;
 }

 #include <bits/stdc++.h>
 using namespace std;

 void change(const int *pt) {
     int *pc = const_cast<int *> (pt);
     *pc = ;
 }

 int main() {
     int pop1 = ;
     const int pop2 = ;
     cout << pop1 << ' ' << pop2 << endl;
     change(&pop1);
     change(&pop2);
     cout << pop1 << ' ' << pop2 << endl;
     return ;
 }

——written by Lyon