Compilare: user.cpp: In function ‘int main()’: user.cpp:34:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k,layer=0,max; ^ user.cpp:34:13: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k,layer=0,max; ^ user.cpp:36:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pcb.in","r",stdin); ^ user.cpp:37:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pcb.out","w",stdout); ^