//中国银行股票投资回报与风险分析 -by Freddy
#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
using namespace std;
vector<double> x;
double mx_fun(vector<double> x, double mx)
{ mx=0.0;
for (int i=0;i<x.size();i++){
mx+=x[i]/x.size();
}
return mx;
}
double vx_fun(vector<double> x, double vx, double mx)
{ vx=0.0;
for (int i=0;i<x.size();i++){
vx+=pow(x[i]- mx_fun(x,mx),2)/(x.size()-1);
}
return vx;
}
int main(){
ifstream source1("bank of china.txt");
double a;
if (source1.is_open()){
while(!source1.eof()){
source1 >> a;
x.push_back(a);
}
source1.close();
}
double beta=0.0,mx=0.0, my=0.0,vx=0.0,vy=0.0;
double mean= mx_fun(x, mx);
double var=vx_fun(x,vx, mx);
double sdv=sqrt(var);
cout<< "The average return of Bank of china is : " << mean<<endl;
cout<<"The volatility(standard deviation) of Bank of china is : "<< sdv <<endl;
return 0;
|