Compilare: user.cpp: In function ‘int main()’: user.cpp:23:8: warning: unused variable ‘i’ [-Wunused-variable] ll i=1, j=1; ^ user.cpp:23:13: warning: unused variable ‘j’ [-Wunused-variable] ll i=1, j=1; ^ user.cpp:25:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.in", "r", stdin); ^ user.cpp:26:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.out", "w", stdout); ^ user.cpp:30:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &a1, &a2, &a3, &a4, &a5); ^