Compilare: user.cpp: In function ‘void read()’: user.cpp:77:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "matperm2.in" , "r" , stdin ) ; ^ user.cpp:78:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d %d" , &N , &M , &P ) ; ^ user.cpp:83:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &orderLine[i] ) ; ^ user.cpp:86:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &orderColomn[i] ) ; ^ user.cpp:90:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &Q ) ; ^ user.cpp:94:61: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d %d %d" , &x0 , &y0 , &x1 , &y1 ) ; ^