689458_0_0_26900.c 689458_0_0_26900.c(13) : error C2143: 语法错误 : 缺少“;”(在“类型”的前面) 689458_0_0_26900.c(16) : error C2065: “sum” : 未声明的标识符 689458_0_0_26900.c(17) : error C2065: “f_sum” : 未声明的标识符