Compilare: user.cpp: In function ‘void solve()’: user.cpp:22:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp: In function ‘void read()’: user.cpp:11:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divk.in", "r", stdin); ^ user.cpp:12:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &k, &a, &b); ^ user.cpp:16:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp: In function ‘void write()’: user.cpp:34:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divk.out", "w", stdout); ^