当我看到标签“c++”和“运算符重载”时,我的心灵警报开启了。
C++ 运算符重载很复杂,一些运算符如“()”或“->”使其更加困难。
我建议,在重载运算符之前,创建一个具有相同目的的全局函数或方法,测试它是否有效,然后用运算符替换它。
全局好友函数示例:
class c {
private:
int n[10];
public:
c();
~c();
// int operator()(int i) { return n[i]; }
// there is a friend global function, that when receives a "c" object,
// as a parameter, or declares a "c" object, as a local variable,
// this function, will have access to the "public" members of "c" objects,
// the "thisref" will be removed, when turned into a method
friend int c_subscript(c thisref, int i) ;
};
int c_subscript(c* thisref, int i)
{
return c->n[i];
}
int main()
{
c* objC() = new c();
// do something with "objcC"
int x = c_subscript(objC, 3);
// do something with "x"
return 0;
} // int main(...)
局部函数(“方法”)示例:
class c {
private:
int n[10];
public:
c();
~c();
// int operator()(int i) { return n[i]; }
int subscript(int i) ;
};
int c::subscript(int i)
{
return this.n[i];
}
int main()
{
c* objC() = new c();
// do something with "objcC"
int x = c->subscript(objC, 3);
// do something with "x"
return 0;
} // int main(...)
并且,最后使用重载运算符:
class c {
private:
int n[10];
public:
c();
~c();
int subscript(int i) ;
int operator()(int i) { return this.subscript(i); }
};
int c::subscript(int i)
{
return this.n[i];
}
int main()
{
c* objC() = new c();
// do something with "objcC"
int x = c->subscript(3);
// do something with "x"
int x = c(3);
// do something with "x"
return 0;
} // int main(...)
请注意,在最后一个示例中,我使用唯一标识符保留方法。
干杯。