689463_0_0_4343.c 689463_0_0_4343.c(13) : error C2143: 语法错误 : 缺少“;”(在“类型”的前面) 689463_0_0_4343.c(16) : error C2065: “sum” : 未声明的标识符 689463_0_0_4343.c(17) : error C2065: “f_sum” : 未声明的标识符