Compilare: user.cpp: In function ‘int main()’: user.cpp:49:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; (1 << i) <= v.size(); printf("\n"), ++i) ^ user.cpp:58:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < v.size() && marked[v[j]]) j++; ^ user.cpp:59:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < v.size() && !marked[v[j]]) j++; ^ user.cpp:60:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == v.size()) continue; ^ user.cpp:64:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < norm.size(); ++j) ^ user.cpp:66:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < norm.size(); ++j) ^ user.cpp:19:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("specsort.in","r",stdin); ^ user.cpp:20:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("specsort.out","w",stdout); ^ user.cpp:22:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:25:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] where[a[i]] = i; ^