View Compilation Error

0_0_26168754_4867.cpp: In function 'int main()':
0_0_26168754_4867.cpp:10:37: error: 'strcmp' was not declared in this scope
   if (!target&&strcmp(letters, "END") == 0)
                                     ^
0_0_26168754_4867.cpp:13:37: error: 'memset' was not declared in this scope
   memset(result, '0', sizeof(result));
                                     ^
0_0_26168754_4867.cpp:14:27: error: 'strlen' was not declared in this scope
   int len = strlen(letters);
                           ^