Compilare: user.cpp: In function ‘void dec(int)’: user.cpp:63:9: warning: unused variable ‘p’ [-Wunused-variable] int p, i; ^ user.cpp: In function ‘void read()’: user.cpp:20:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc.in", "r", stdin); ^ user.cpp:21:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc.out", "w", stdout); ^ user.cpp:22:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &b, &c); ^ user.cpp:25:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i].a); ^