引用与指针那些事 (opens new window)

函数指针和指针函数

#include <iostream>
using namespace std;
/*! \brief Possible kinds of TypeVars. */
enum TypeKind {

 kType = 0,
 /*! \brief Template variable in shape expression. */
 kShapeVar = 1,
 kBaseType = 2,
 kConstraint = 4,
 kAdtHandle = 5,
 kTypeData = 6
};

union TypeValue {
 char c;
 unsigned char uc;
 long l;
};

const double* f1(const double arr[], int n) { return arr; }
const double* f2(const double arr[], int n) { return arr + 1; }
const double* f3(const double* arr, int n) { return arr + 2; }

int main(int argc, char* argv[]) {
 TypeKind a = kShapeVar;
 TypeValue b;
 b.c = 'L';
 cout << "test for union:b.c " << b.c << endl;

 b.l = 1234;
 cout << "test for union:b.l " << b.l << endl;
 cout << "test for union:b.c " << b.c << endl;

 double at[3] = {12.1, 3.4, 4.5};
 const double* (*pfunc)(const double*, int) = f1;
 cout << "test for function pointer: Point1: " << *pfunc(at, 3) << endl;

 const double* (*pfunc1[3])(const double*, int) = {f1, f2, f3};
 cout << "test for function pointer: Point1: " << *pfunc1[2](at, 3) << endl;
 cout << "test for function pointer: Point12: " << *pfunc1[0](at, 3) << endl;
 cout << "test for function pointer: Point1: " << *((*pfunc1[2])(at, 3)) << endl;
 cout << "test for enum: " << a << endl;

 cout << "hello word" << endl;



 cout << "test for singleton";

 return 0;

}