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0_0_23079663_20281.cpp
0_0_23079663_20281.cpp(4) : error C3874: “main”的返回类型应为“int”而非“double”
0_0_23079663_20281.cpp(9) : error C2668: “sqrt”: 对重载函数的调用不明确
        VC2013\INCLUDE\math.h(1251): 可能是“long double sqrt(long double) throw()”
        VC2013\INCLUDE\math.h(1135): 或       “float sqrt(float) throw()”
        VC2013\INCLUDE\math.h(521): 或       “double sqrt(double)”
        尝试匹配参数列表“(int)”时