Compilare: main.cpp: In function 'int main()': main.cpp:44:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < needleHash.size(); ++i) { ~~^~~~~~~~~~~~~~~~~~~ main.cpp:54:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = needle.size(); i < haystack.size(); ++i) { ~~^~~~~~~~~~~~~~~~~ main.cpp:55:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < haystackHash.size(); ++j) ~~^~~~~~~~~~~~~~~~~~~~~ main.cpp:30:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in", "r", stdin); ^ main.cpp:31:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out", "w", stdout); ^