Compilare: user.cpp: In function ‘int main()’: user.cpp:115:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k; ^ user.cpp:115:13: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k; ^ user.cpp:112:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tree2.in","r",stdin); ^ user.cpp:113:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tree2.out","w",stdout); ^ user.cpp:114:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:117:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&p[i].x,&p[i].y); ^