Compilare: user.cpp: In function ‘int main()’: user.cpp:63:19: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&n); ^ user.cpp:67:19: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&x); ^ user.cpp:68:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] if (x==1) fscanf(in,"%d",&y),add(y); ^ user.cpp:70:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] if (x==2) fscanf(in,"%d",&y),use[y]=1; ^ user.cpp: In function ‘void down(int)’: user.cpp:8:14: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized] int aux,ok=1,r; ^