我整理了以下例子:实现C++后缀增量操作
#include <iostream>
#include <iterator>
using namespace std;
class myiterator : public iterator<input_iterator_tag, int>
{
int* p;
public:
myiterator(int* x) :p(x) {}
myiterator(const myiterator& mit) : p(mit.p) {}
myiterator& operator++() {++p;return *this;}
myiterator& operator++(int) {myiterator tmp(*this); operator++(); return tmp;}
bool operator==(const myiterator& rhs) {return p==rhs.p;}
bool operator!=(const myiterator& rhs) {return p!=rhs.p;}
int& operator*() {return *p;}
};
int main() {
int numbers[]={10,20,30,40,50};
myiterator beginning(numbers);
myiterator end(numbers+5);
for (myiterator it=beginning; it!=end; it++)
cout << *it << " ";
cout << endl;
return 0;
}
从cplusplus.com/reference和我得到的编译器警告:
iterator.cpp: In member function 'myiterator& myiterator::operator++(int)':
iterator.cpp:13: warning: reference to local variable 'tmp' returned
这里有什么错?后缀签名应该是myiterator operator++(int)
,即按值返回?
是否有某处定义了后缀签名在STL迭代器上的样子?
cplusplus.com是有用的,但不是权威的。在这种情况下,它会伤害你。如果你看一下实际的STL代码,你会发现迭代器经常被返回值,而cplusplus.com并没有告诉你可以这样做。 – 2010-12-03 16:39:28
http://stackoverflow.com/questions/3181211/prefix-postfix-increment-operators – 2015-06-17 10:22:35