View Compilation Error

0_0_25101730_333.cpp: In function 'int main()':
0_0_25101730_333.cpp:54:36: error: 'strcmp' was not declared in this scope
         if (n==0 && strcmp(s, "END")==0)
                                    ^
0_0_25101730_333.cpp:56:35: error: 'memset' was not declared in this scope
         memset(vis, 0, sizeof(vis));
                                   ^
0_0_25101730_333.cpp:57:23: error: 'strlen' was not declared in this scope
         len = strlen(s);
                       ^