重載朋友操作符<for Template類現(xiàn)在，我在stackoverflow網(wǎng)站上讀到了幾個關(guān)于我的問題，但這些問題似乎都解決不了我的問題?；蛘呶易鲥e了.超載<<如果我把它變成內(nèi)聯(lián)函數(shù)就行了。但我怎樣才能讓它在我的案子里起作用呢？warning: friend declaration std::ostream& operator<<(std::ostream&, const D<classT>&)' declares a non-template functionwarning: (if this is not what you intended, make sure the function template has already been declared and add <> after the function name here) -Wno-non-template-friend disables this warning/tmp/cc6VTWdv.o:uppgift4.cc:(.text+0x180): undefined reference to operator<<(std::basic_ostream<char, std::char_traits<char> >&, D<int> const&)'
collect2: ld returned 1 exit status守則：template <class T>T my_max(T a, T b){
if(a > b)
return a;
else
return b;}template <class classT>class D{public:
D(classT in)
: d(in) {};
bool operator>(const D& rhs) const;
classT operator=(const D<classT>& rhs);
friend ostream& operator<< (ostream & os, const D<classT>& rhs);private:
classT d;};int main(){
int i1 = 1;
int i2 = 2;
D<int> d1(i1);
D<int> d2(i2);
cout << my_max(d1,d2) << endl;
return 0;}template <class classT>ostream& operator<<(ostream &os, const D<classT>& rhs){
os << rhs.d;
return os;}
3 回答
蝴蝶不菲
TA貢獻1810條經(jīng)驗 獲得超4個贊
template <typename SclassT>friend ostream& operator<< (ostream & os, const D<SclassT>& rhs);
SclassTclassT
template <typename SclassT>ostream& operator<< (ostream & os, const D<SclassT>& rhs){
// body..}
胡說叔叔
TA貢獻1804條經(jīng)驗 獲得超8個贊
#include <iostream>using namespace std;template <class T>T my_max(T a, T b){
if(a > b)
return a;
else
return b;}template <class classT>class D{public:
D(classT in)
: d(in) {};
bool operator>(const D& rhs) const {
return (d > rhs.d);
}
classT operator=(const D<classT>& rhs);
friend ostream& operator<< (ostream & os, const D& rhs) {
os << rhs.d;
return os;
}private:
classT d;};int main(){
int i1 = 1;
int i2 = 2;
D<int> d1(i1);
D<int> d2(i2);
cout << my_max(d1,d2) << endl;
return 0;}- 3 回答
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