Compilare: user.cpp: In function ‘int main()’: user.cpp:5:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "qmatrix.in", "r", stdin ); ^ user.cpp:6:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "qmatrix.out", "w", stdout ); ^ user.cpp:9:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d%d%d", &n, &x, &y, &q ); ^ user.cpp:24:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "\n%c%d%d", &cer, &p, &k ); ^