View Compilation Error

0_0_21640322_21942.cpp: In function 'int main()':
0_0_21640322_21942.cpp:9:33: error: 'strcmp' was not declared in this scope
  while (gets(buf)&&strcmp(buf,"")){
                                 ^
0_0_21640322_21942.cpp:10:21: error: 'strlen' was not declared in this scope
   int len=strlen(buf);
                     ^