Compilare: user.cpp: In function ‘int main()’: user.cpp:61:17: warning: unused variable ‘plt’ [-Wunused-variable] int plt = P[i][j]; ^ user.cpp:58:13: warning: unused variable ‘plm’ [-Wunused-variable] int plm = P[i][0]; ^ user.cpp:41:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mate.in", "r", stdin); ^ user.cpp:42:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mate.out", "w", stdout); ^ user.cpp:43:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("debug.err", "w", stderr); ^ user.cpp:47:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:49:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &value); ^