首AC，有点复杂，将就着看吧

#include<bits/stdc++.h>
using namespace std;
double n,totality=0,average,cmax=0;
double a[330];
int findmax(double c[],int n){
	double maxn=-1;
	int ans=0;
	for(int i=0;i<n;i++){
		if(maxn<c[i]){
			maxn=c[i];
			ans=i;		
		}
	}
	return ans;
}
int findmin(double a[],int n){
	double minn=1e9+5;
	int ans=0;
	for(int i=0;i<n;i++){
		if(minn>a[i]&&a[i]>=0){
			minn=a[i];
			ans=i;		
		}
	}
	return ans;
}
int main(){
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>a[i];
		totality+=a[i];
	}
	totality-=a[findmax(a,n)];
	totality-=a[findmin(a,n)];
	average=totality/(n-2);
	for(int i=0;i<n;i++){
		if(i!=findmax(a,n)&&i!=findmin(a,n))cmax=max(cmax,abs(a[i]-average)); 
	}
	cout<<fixed<<setprecision(2)<<average<<' '<<cmax;
	return 0;
}