建设银行透支卡:c++的程序解释

//: C12:SmartPointer.cpp
#include <iostream>
#include <vector>
#include "../require.h"
using namespace std;

class Obj {
static int i, j;
public:
void f() const { cout << i++ << endl; }
void g() const { cout << j++ << endl; }
};

// Static member definitions:
int Obj::i = 47;
int Obj::j = 11;

// Container:
class ObjContainer {
vector<Obj*> a;
public:
void add(Obj* obj) { a.push_back(obj); }
friend class SmartPointer;
};

class SmartPointer {
ObjContainer& oc;
int index;
public:
SmartPointer(ObjContainer& objc) : oc(objc) {
index = 0;
}
// Return value indicates end of list:
bool operator++() { // Prefix
if(index >= oc.a.size()) return false;
if(oc.a[++index] == 0) return false;
return true;
}
bool operator++(int) { // Postfix
return operator++(); // Use prefix version
}
Obj* operator->() const {
require(oc.a[index] != 0, "Zero value "
"returned by SmartPointer::operator->()");
return oc.a[index];
}
};

int main() {
const int sz = 10;
Obj o[sz];
ObjContainer oc;
for(int i = 0; i < sz; i++)
oc.add(&o[i]); // Fill it up
SmartPointer sp(oc); // Create an iterator
do {
sp->f(); // Pointer dereference operator call
sp->g();
} while(sp++);
} ///:~