0_0_38128705_24455.cpp 0_0_38128705_24455.cpp(51) : error C2065: “sum”: 未声明的标识符 0_0_38128705_24455.cpp(55) : error C2065: “sum”: 未声明的标识符 0_0_38128705_24455.cpp(56) : error C2065: “sum”: 未声明的标识符