View Compilation Error

0_0_28116587_12841.cpp: In function 'int main()':
0_0_28116587_12841.cpp:16:37: error: 'memset' was not declared in this scope
     memset(hash, false, sizeof(hash));
                                     ^
0_0_28116587_12841.cpp:20:28: error: 'strlen' was not declared in this scope
     for (int i=0;i<strlen(c);i++)
                            ^
0_0_28116587_12841.cpp:29:29: error: 'strlen' was not declared in this scope
     for (int i=0;i<=strlen(c)-nc;i++)
                             ^
0_0_28116587_12841.cpp:40:26: error: expected '}' at end of input
     cout << count << endl;
                          ^