View Compilation Error

0_0_4355970_21817.cpp
0_0_4355970_21817.cpp(32) : error C2668: “pow” : 对重载函数的调用不明确
        VC\include\math.h(532): 可能是“double pow(double,int)”
        VC\include\math.h(195): 或       “double pow(double,double)”
        试图匹配参数列表“(double, std::basic_string<_Elem,_Traits,_Ax>::size_type)”时
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>,
            _Ax=std::allocator<char>
        ]