Compilare: user.cpp: In function ‘void solve()’: user.cpp:18:9: warning: unused variable ‘x’ [-Wunused-variable] int x = n, i, j; ^ user.cpp: In function ‘void read()’: user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "ab2.in", "r", stdin ); ^ user.cpp:11:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d%d", &n, &a, &b ); ^ user.cpp: In function ‘void solve()’: user.cpp:17:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "ab2.out", "w", stdout ); ^