Compilare: user.cpp: In function ‘int main()’: user.cpp:43:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < h [j].size() && !found; ++i) ^ user.cpp:61:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < h [j].size() && !found; ++k) ^ user.cpp:19:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc2.in", "r", stdin); ^ user.cpp:20:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc2.out", "w", stdout); ^ user.cpp:23:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n", s); ^ user.cpp:33:22: warning: ‘l’ may be used uninitialized in this function [-Wmaybe-uninitialized] for (i = 0;s [i] && i < l; i++) { ^