#include<bits/stdc++.h>
#define int long long
using namespace std;
struct st{
	double y;
	double s;
	double w;
}a[105];
double yp,yn;
double sp,sn;
double wp,wn;
double pp,x;
int n;
char m;
int sum = 0,nama = -1e18;
signed main(){
	cout<<"录入个数：";
	cin>>n;	
	//读入个数
	yn = n;
	sn = n;
	wn = n;
	system("cls");
	for(int i = 1;i<=n;i++)
	{
//		cout<<"学生"<<i<<"姓名：";cin>>a[i].na;  //读入姓名
//		sum = 0;
//		m = getchar();
		cout<<"学生"<<i<<"语文成绩：";
		cin>>x;
		if(x<=100 && x>=0)
		{
			a[i].y = x;
			yp += x;
		}else{
			yn--;
		}
		//读入语文
		cout<<"学生"<<i<<"数学成绩：";
		if(x<=100 && x>=0)
		{
			a[i].s = x;
			sp += x;
		}else{
			sn--;
		}
		//读入数学
		cout<<"学生"<<i<<"外语成绩：";
		if(x<=100 && x>=0)
		{
			a[i].w = x;
			wp += x;
		}else{
			wn--;
		}
		//读入外语
		system("cls");	
	}
	
//	|学号|语文 |数学 |外语 |平均 |
//	| 01 |100.0|100.0|100.0|100.0|
	
	cout<<"|学号|语文 |数学 |外语 |平均 |\n";
	//|学号|语文 |数学 |外语 |平均 |
	//------------------------------
	//| 01 |100.0| 90.0| 1.0 | 63.0|
	//3位数->|xxx.x|
	//2位数->| xx.x|
	//1位数->| x.x |
	for(int i = 1;i<=n;i++)
	{
		cout<<"| ";
		printf("%02d",i);
		cout<<" |";
		if(a[i].y>=0 && a[i].y<=9.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].y<<" |";
		}
		else if(a[i].y>=10 && a[i].y<=99.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].y<<"|";
		}
		else
		{
			cout<<fixed<<setprecision(1)<<a[i].y<<"|";
		}
		//语文
		if(a[i].s>=0 && a[i].s<=9.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].s<<" |";
		}
		else if(a[i].s>=10 && a[i].s<=99.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].s<<"|";
		}
		else
		{
			cout<<fixed<<setprecision(1)<<a[i].s<<"|";
		}
		//数学
		if(a[i].w>=0 && a[i].w<=9.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].w<<" |";
		}
		else if(a[i].w>=10 && a[i].w<=99.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<a[i].w<<"|";
		}
		else
		{
			cout<<fixed<<setprecision(1)<<a[i].w<<"|";
		}
		//外语
		double p = (a[i].y+a[i].s+a[i].w)/3;
		pp += p;
		if(p>=0 && p<=9.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<p<<" |\n";
		}
		else if(p>=10 && p<=99.5)
		{
			cout<<" "<<fixed<<setprecision(1)<<p<<"|\n";
		}
		else
		{
			cout<<fixed<<setprecision(1)<<p<<"|\n";
		}
		//平均
	}
	cout<<"------------------------------\n";/*|求和|*/
	//								       ^-|---------|
	double yp1 = yp;
	double sp1 = sp;
	double wp1 = wp;
	double pp1 = pp;
	yp /= double(yn);
	sp /= double(sn);
	wp /= double(wn);
	pp /= double(n);
	cout<<"|平均|";
	if(yp>=0 && yp<=9.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<yp<<" |";
	}
	else if(yp>=10 && yp<=99.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<yp<<"|";
	}
	else
	{
		cout<<fixed<<setprecision(1)<<yp<<"|";
	}
	//语文
	if(sp>=0 && sp<=9.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<sp<<" |";
	}
	else if(sp>=10 && sp<=99.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<sp<<"|";
	}
	else
	{
		cout<<fixed<<setprecision(1)<<sp<<"|";
	}
	//数学
	if(wp>=0 && wp<=9.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<wp<<" |";
	}
	else if(wp>=10 && wp<=99.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<wp<<"|";
	}
	else
	{
		cout<<fixed<<setprecision(1)<<wp<<"|";
	}
	//外语
	if(pp>=0 && pp<=9.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<pp<<" |\n";
	}
	else if(pp>=10 && pp<=99.5)
	{
		cout<<" "<<fixed<<setprecision(1)<<pp<<"|\n";
	}
	else
	{
		cout<<fixed<<setprecision(1)<<pp<<"|\n";
	}
	//平均
	return 0;
}

其他略 程序的第9行，第11列报错信息为[错误] 'double yn' redeclared as different kind of entity