View Compilation Error

0_0_18328229_11575.cpp: In function 'Mat operator*(const Mat&, const Mat&)':
0_0_18328229_11575.cpp:18:33: error: 'memset' was not declared in this scope
     memset(c.mat, 0, sizeof(Mat));
                                 ^
0_0_18328229_11575.cpp: In function 'Mat operator+(const Mat&, const Mat&)':
0_0_18328229_11575.cpp:33:33: error: 'memset' was not declared in this scope
     memset(c.mat, 0, sizeof(Mat));
                                 ^
0_0_18328229_11575.cpp: In function 'Mat operator^(Mat, int)':
0_0_18328229_11575.cpp:44:33: error: 'memset' was not declared in this scope
     memset(c.mat, 0, sizeof(Mat));
                                 ^
0_0_18328229_11575.cpp: In function 'int main()':
0_0_18328229_11575.cpp:67:37: error: 'memset' was not declared in this scope
         memset(A.mat, 0, sizeof(Mat));
                                     ^