最近看代码的时候,发现编码里面有很多 :: 。
return_type namespace_name::class_name::function_name(Args..)
{
::global_function_name();
local_function_name();
return return_value;
}
感觉是个好习惯。
::的用法主要是解决可见性和冲突问题, namespace,class,全局。。
举个例子:
#include <iostream>
#include <string>
std::string name_ = "global";
void fun() {
std::cout << "global fun" << std::endl;
}
class A {
public:
A(std::string name) : name_(name) {
std::cout << "construct - " << name_ << std::endl;
}
void fun() {
std::cout << "local fun" << std::endl;
}
void test() {
std::cout << name_ << std::endl;
fun();
::fun();
std::cout << ::name_ << std::endl;
}
~A() {
std::cout << "destruct - " << name_ << std::endl;
}
private:
std::string name_;
};
int main()
{
A a("local");
a.test();
return 0;
}
输出结果为:
construct - local
local
local fun
global fun
global
destruct - local