0_0_39294489_19395.cpp 0_0_39294489_19395.cpp(8) : error C2065: “cin”: 未声明的标识符 0_0_39294489_19395.cpp(18) : error C2065: “cin”: 未声明的标识符 0_0_39294489_19395.cpp(35) : error C2065: “cout”: 未声明的标识符