int b = 10; 
int c = 15; 
const int *p1 = &b; 
//*p1 = 12; /* 错误 */
   p1 = &c; /* 正确*/
   cout<< *p1 << endl;

int * const p2 = &b; 
*p2 = c; /* 正确*/                                                                      
   //p2 = &c; /* 错误 */
   cout << *p2 << endl;

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