Compilare: main.cpp: In function 'int main()': main.cpp:166:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < comp[i].size(); j++){ ~~^~~~~~~~~~~~~~~~ main.cpp:167:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] printf("%d%c", comp[i][j], " \n"[j + 1 == comp[i].size()]); ~~~~~~^~~~~~~~~~~~~~~~~ main.cpp:154:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] ri2(n, m); ^ main.cpp:157:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] ri2(u, v); ^