我想要两个相似的模板,一个带有1个参数,另一个带有2个参数：
template<typename T1,typename T2=void>
struct foo {
T1 m_t1;
T2 m_t2;
foo(T1 t1,T2 t2) : m_t1(t1),m_t2(t2) {}
T1 t1() { return m_t1; }
T2 t2() { return m_t2; }
};
template<typename T1>
struct foo<T1,void> {
T1 m_t1;
foo(T1 t1) : m_t1(t1) {}
T1 t1() { return m_t1; }
};
@R_404_323@
解决此问题的唯一方法是在基类中拥有尽可能多的代码.例如：
template<typename T1>
struct foo_base {
T1 m_t1;
explicit foo_base(T1 t1) : m_t1(t1) {}
T1 t1() const { return m_t1; }
};
template<typename T1,typename T2=void>
struct foo : foo_base<T1> {
T2 m_t2;
foo(T1 t1,T2 t2) : foo_base<T1>(t1),m_t2(t2) {}
T2 t2() const { return m_t2; }
};
template<typename T1>
struct foo<T1,void> : foo_base<T1> {
explicit foo(T1 t1) : foo_base<T1>(t1) {}
};
