View Compilation Error

0_0_17580355_21087.cpp: In function 'int main()':
0_0_17580355_21087.cpp:17:29: error: 'strcmp' was not declared in this scope
  while (strcmp(str1, "START") == 0 && strcmp(str1, "ENDOFINPUT") != 0){
                             ^
0_0_17580355_21087.cpp:18:31: error: 'memset' was not declared in this scope
   memset(str2, 0, sizeof(str2));
                               ^
0_0_17580355_21087.cpp:20:24: error: 'strlen' was not declared in this scope
   int len = strlen(str2);
                        ^