Compilare: user.cpp: In function ‘int main()’: user.cpp:24:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:21:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "deque.in", "r", stdin ); ^ user.cpp:22:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "deque.out", "w", stdout ); ^ user.cpp: In function ‘void Read()’: user.cpp:56:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d", &N, &K ); ^ user.cpp:59:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &a[i] ); ^ user.cpp: In function ‘void Next()’: user.cpp:79:40: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] std::fread( c, 1, MAXC, stdin ); ^