(9) : error C2668: “abs”: 对重载函数的调用不明确
        VC8\include\math.h(539): 可能是“long double abs(long double)”
        VC8\include\math.h(491): 或“float abs(float)”
        VC8\include\math.h(487): 或“double abs(double)”
        VC8\include\math.h(485): 或“long abs(long)”
        VC8\include\stdlib.h(415): 或“int abs(int)”
        试图匹配参数列表“(__int64)”时