您如何为成员使用非默认构造函数?
我有两个班
class a {
public:
a(int i);
};
class b {
public:
b(); //Gives me an error here, because it tries to find constructor a::a()
a aInstance;
}
我怎样才能让 aInstance
用 a(int i)
实例化,而不是尝试搜索默认构造函数?基本上,我想从 b
的构造函数中控制 a
的构造函数的调用.
How can I get it so that aInstance
is instantiated with a(int i)
instead of trying to search for a default constructor? Basically, I want to control the calling of a
's constructor from within b
's constructor.
推荐答案
你需要在构造函数初始化列表中显式调用a(int):
You need to call a(int) explicitly in the constructor initializer list:
b() : aInstance(3) {}
其中 3 是您要使用的初始值.虽然它可以是任何整数.有关订单的重要说明和其他注意事项,请参阅评论.
Where 3 is the initial value you'd like to use. Though it could be any int. See comments for important notes on order and other caveats.
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