<分区>
Possible Duplicate:
Default constructor with empty brackets
Instantiate class with or without parentheses?
程序:
class Foo
{
public:
Foo ( int bar = 1 )
{
cout << "bar=" << bar;
}
};
int main() {
cout << "0 - ";
Foo foo_0 ( 0 ) ;
cout << '\n';
cout << "1 - ";
Foo foo_1 ();
cout << '\n';
cout << "2 - ";
Foo foo_4;
cout << '\n';
return 0;
}
输出:
0 - bar=0
1 -
2 - bar=1
问题:为什么示例 #1 不起作用，而示例 #0 和 #2 可以？