View Compilation Error

0_0_17013459_31970.cpp: In function 'int main()':
0_0_17013459_31970.cpp:12:31: error: 'memset' was not declared in this scope
   memset(Index,0,sizeof(Index));
                               ^
0_0_17013459_31970.cpp:13:23: error: 'strlen' was not declared in this scope
   int len = strlen(str);
                       ^