View Compilation Error

0_0_25002410_10404.cpp: In function 'int main()':
0_0_25002410_10404.cpp:23:31: error: 'strcmp' was not declared in this scope
  if( n==0 && !strcmp(key,"END") )
                               ^
0_0_25002410_10404.cpp:26:18: error: 'strlen' was not declared in this scope
  lenth=strlen(key);
                  ^