买验3 BC File Edit Search Run Compile Debug Project Options Window He E6-4. CPP printf(" please input the number of students: ">i scanf( d",&n) scanf("f,&s); sum=sum+s j ave=sum/n i printf( ave=6.2f\n", ave); getch) 17:68=1 sum: Undefined symbol 'sum sum: Undefined symbo sum 1: Undefined symbol 'i .s: Undefined symbols i: Undefined symbol 'i S: Undefined symbol‘s F1 Help F2 Save F3 Open Alt-F9 Compile F9 Make F10 Menusum: Undefined symbol ‘sum’ i: Undefined symbol ‘i’ s: Undefined symbol ‘s’ 实验3