View Compilation Error

0_0_27654778_27906.cpp: In function 'int main()':
0_0_27654778_27906.cpp:12:25: error: 'memset' was not declared in this scope
   memset(w, 0, sizeof(w));
                         ^
0_0_27654778_27906.cpp:15:18: error: 'strcmp' was not declared in this scope
   if (strcmp(s, w) == 0)//比较
                  ^