#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
int i,j,s1[3]={0,0,0},s2[4]={0,0,0,0};
double ave1[3],ave2[4];
int a[4][3]={{89,78,56},{88,99,100},{72,80,61},{60,70,75}};
for(i=0;i<3;i++)
{for(j=0;j<4;j++)
s1[i]=s1[i]+a[j][i];
ave1[i]=double(s1[i])/4;}
cout<<"每门课程的学生平均成绩:"<<endl;
for(i=0;i<3;i++)
cout<<"课程"<<i+1<<"的学生平均成绩为："<<ave1[i]<<endl;
for(j=0;j<4;j++)
{for(i=0;i<3;i++)
s2[j]=s2[j]+a[j][i];
ave2[j]=double(s2[j])/3;}
cout<<"每个学生的各门课程平均成绩:"<<endl;
for(j=0;j<4;j++)
cout<<"学生"<<j+1<<"的各门课程平均成绩为："<<fixed<<setprecision(2)<<ave2[j]<<endl;
return 0;
}