View Compilation Error

0_0_16461491_13517.cpp: In function 'int main()':
0_0_16461491_13517.cpp:61:42: error: 'strcmp' was not declared in this scope
  while(scanf("%s", str)&&strcmp(str,"END")!=0){
                                          ^
0_0_16461491_13517.cpp:63:19: error: 'strlen' was not declared in this scope
   len = strlen(str);
                   ^