Mã nộp #19918 | Chọn cạnh tam giác

Main.cc: In function ‘void DemSo(int, int, int*, int*)’:
Main.cc:30:12: error: return-statement with a value, in function returning 'void' [-fpermissive]
     return dem;
            ^~~
Main.cc: In function ‘void nhapmang(int*, int)’:
Main.cc:6:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~