Compilare: main.cpp: In function 'int main()': main.cpp:85:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (l < pr[i].size ()) { ~~^~~~~~~~~~~~~~~ main.cpp:86:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (r < pr[i].size () - 1 && not_good + pr[i][r + 1] - pr[i][r] - 1 <= 1) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:67:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("deletegcd.in", "r", stdin); ^ main.cpp:68:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("deletegcd.out", "w", stdout); ^ main.cpp: In function 'char advance()': main.cpp:12:35: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buffer, SIZE, 1, stdin); ^