View Compilation Error

0_0_19009294_4026.cpp: In function 'int main()':
0_0_19009294_4026.cpp:11:23: error: 'memset' was not declared in this scope
   memset(s,0,sizeof(s));
                       ^
0_0_19009294_4026.cpp:13:15: error: 'strlen' was not declared in this scope
   len=strlen(s);
               ^