Mean and Standard Deviation-从文件中读取数据计算其平均数和标准差

//Meanand Standard Deviation-从文件中读取数据计算其平均数和标准差
#include<iostream>
#include<fstream>
#include<cstdlib>
#include<cmath>

int main()
{
usingnamespace std;
ifstream fin;
ofstream fout;

double aver,tem,count =0,sum = 0;
double stadev;

fin.open("numbers.dat");
if(fin.fail())
{
cout<<"Input file opening failed.\n";
exit(1);
}

//fin>>tem;
//sum = tem;
while(fin>>tem)
{
count++;
sum += tem;
}

cout<<"sum ="<<sum<<endl;
cout<<"count = "<<count<<endl;
aver = sum/count;

fin.close();

fin.open("numbers.dat");
if(fin.fail())
{
cout<<"Input file opening failed.\n";
exit(1);
}

sum  =0;
fin>>tem;
while(!fin.eof())
{
sum += (tem - aver)*(tem - aver);
fin>>tem;
}

stadev = sqrt(sum / count);

cout<<"The average is "<<aver<<endl;
cout<<"The stadev is "<<stadev<<endl;

fin.close();
return 0;
}

1 2 3 4 5 6

sum=21
count= 6
Theaverage is 3.5
The stadev is1.36931

8 8 8 8 8 8

sum=48
count= 6
Theaverage is 8
The stadev is 0

11.2 1.3 2.4 8.5 7.6 3.7 4.8 6.9 5.0 9.1

sum=60.5
count= 10
Theaverage is 6.05
The stadev is 2.9837