foo.cpp: In function 'int main()':
foo.cpp:17:19: error: 'n' was not declared in this scope
  for (int i=1; i<=n; i++) scanf("%d",T+i);
                   ^
foo.cpp:18:19: error: 'n' was not declared in this scope
  for (int i=1; i<=n; i++) if (!used[i]) search(i,++Svolk,1);
                   ^