Compilare: user.cpp: In function ‘int main()’: user.cpp:24:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); i+=10) ^ user.cpp: In function ‘void read()’: user.cpp:11:40: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d%d%d", &n, &a, &b, &c); ^