View Compilation Error

0_0_18272682_9374.cpp: In function 'M Add(M, M)':
0_0_18272682_9374.cpp:11:33: error: 'memset' was not declared in this scope
     memset(res.m,0,sizeof(res.m));
                                 ^
0_0_18272682_9374.cpp: In function 'M Mult(M, M)':
0_0_18272682_9374.cpp:31:33: error: 'memset' was not declared in this scope
     memset(res.m,0,sizeof(res.m));
                                 ^
0_0_18272682_9374.cpp: In function 'M Div(M, int)':
0_0_18272682_9374.cpp:59:33: error: 'memset' was not declared in this scope
     memset(res.m,0,sizeof(res.m));
                                 ^
0_0_18272682_9374.cpp: In function 'M pow(M, int)':
0_0_18272682_9374.cpp:74:33: error: 'memset' was not declared in this scope
     memset(res.m,0,sizeof(res.m));
                                 ^
0_0_18272682_9374.cpp: In function 'int main()':
0_0_18272682_9374.cpp:101:33: error: 'memset' was not declared in this scope
         memset(c.m,0,sizeof(c.m));
                                 ^