Compilare: user.cpp: In function ‘int main()’: user.cpp:91:17: warning: unused variable ‘j’ [-Wunused-variable] int i,m,x,y,j; ^ user.cpp:92:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plan.in","r",stdin); ^ user.cpp:93:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:95:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp:100:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("plan.out","w",stdout); ^