Compilare: user.cpp: In function ‘void read()’: user.cpp:29:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortnet.in", "r", stdin); ^ user.cpp:30:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &m); ^ user.cpp:35:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("<%d,%d> ", &a, &b); ^ user.cpp: In function ‘void write()’: user.cpp:73:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortnet.out", "w", stdout); ^