0_0_26010906_30540.cpp 0_0_26010906_30540.cpp(8) : error C2065: “i”: 未声明的标识符 0_0_26010906_30540.cpp(8) : error C2065: “sum”: 未声明的标识符 0_0_26010906_30540.cpp(9) : error C2065: “sum”: 未声明的标识符