View Compilation Error

0_0_18654350_11574.cpp: In function 'int main()':
0_0_18654350_11574.cpp:13:31: error: 'memset' was not declared in this scope
           memset(c,0,sizeof(c));
                               ^
0_0_18654350_11574.cpp:17:29: error: 'strlen' was not declared in this scope
           int len = strlen(x);
                             ^