Compilare: user.cpp: In function ‘int main()’: user.cpp:87:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[i].size(); ++j) { ^ user.cpp:88:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < v[i][j].size(); ++k) ^ user.cpp:90:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j + 1 < v[i].size()) ^ user.cpp:66:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("litere2.in", "r", stdin); ^ user.cpp:67:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("litere2.out", "w", stdout); ^ user.cpp:69:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, 1000002, stdin); ^