View Compilation Error

0_0_34656727_8562.cpp: In function 'int slove(int)':
0_0_34656727_8562.cpp:41:39: error: 'memset' was not declared in this scope
     memset(match_x,255,sizeof(match_x));    //初始化，-1表示没有匹配到
                                       ^
0_0_34656727_8562.cpp: In function 'int main()':
0_0_34656727_8562.cpp:57:41: error: 'memset' was not declared in this scope
             memset(head,255,sizeof(head));    //初始化连表头
                                         ^