T fref(const T&, const T&);中的const T&,是什么意思？是reference arguments的話&后面不是有一個(gè)value的吧？(象const T&x，const T&y);template <typename T> T fobj(T, T); // arguments are copiedtemplate <typename T>T fref(const T&, const T&); // reference argumentsstring s1("a value");const string s2("another value");fobj(s1, s2); // ok: calls f(string, string), const is ignoredfref(s1, s2); // ok: non const object s1 converted to const referenceint a[10], b[42];fobj(a, b); // ok: calls f(int*, int*)fref(a, b); // error: array types don't match; arguments aren't converted to pointers