为什么sum求和读到输入不是输入的数字而是别的数字？

#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <bits/stdc++.h>
#include <math.h>
#include <string>
#include <cstring>

using namespace std;
//#define PI 3.1415926
double dafen(int n)
{
double sum=0;
int a[1010],max=-1,min=11,i=0;
while(i < n)
{   
    cin >> a[i];
    sum += a[i];
    i++;
    if(a[i] >= max) max = a[i];
    else if(a[i] <= min) min = a[i];
}
sum = sum - max - min;
cout << sum <<endl;
cout << fixed << setprecision(2) << sum/n;
}
int main()
{
int n;
cin >> n;
dafen(n);
return 0;
}