Compilare: user.cpp: In function ‘void preproc()’: user.cpp:22:12: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, timp = 0; ^ user.cpp: In function ‘void read_and_solve()’: user.cpp:47:9: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k, a, b; ^ user.cpp:47:12: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, a, b; ^ user.cpp:49:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.cpp:53:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &a, &b); ^ user.cpp: In function ‘int main()’: user.cpp:74:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minuni.in", "rt", stdin); ^ user.cpp:75:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("minuni.out", "wt", stdout); ^