有这段代码:#includetemplatevoidfun5(){std::cout();return0;}编译时出现编译器错误:$g++klasa.cpp-oklasaklasa.cpp:Infunction‘intmain()’:klasa.cpp:11:10:error:‘dddd’cannotappearinaconstant-expressionklasa.cpp:11:16:error:nomatchingfunctionforcallto‘fun5()’klasa.cpp:11:16:note:candidateis:klasa.cpp:4:6:note:template