Compilare: user.cpp: In function ‘int main()’: user.cpp:59:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(poz[j] < v[j].size() && v[j][poz[j]] <= i) { ~~~~~~~^~~~~~~~~~~~~ user.cpp: In function ‘char next_ch()’: user.cpp:23:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, DIM, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:42:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("infinitywar.in", "r", stdin); // Thanos ^ user.cpp:43:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("infinitywar.out", "w", stdout); // Thanos ^