View Compilation Error

0_0_22317943_19730.cpp: In function 'int main()':
0_0_22317943_19730.cpp:13:24: error: 'strcmp' was not declared in this scope
   if (!strcmp(a,"START"))
                        ^
0_0_22317943_19730.cpp:16:21: error: 'strlen' was not declared in this scope
   for(i=0;i<strlen(a);i++)
                     ^
0_0_22317943_19730.cpp:27:23: error: 'strcmp' was not declared in this scope
   if (!strcmp(a, "END"))
                       ^