Spearsman rank co-efficient

#include <iostream> #include <cmath> #include <vector> #include <algorithm> #include <utility> #include <iomanip> using namespace std; vector<double> power(vector<double> a, double b) { vector<double> ret; for (int i = 0; i < a.size() ; i++) { ret.push_back(pow(a[i], b)); } return ret; } double sumarr(vector<double> a) { double sss = 0; for (int i = 0; i < a.size() ; i++) { sss += a[i]; } return sss; } vector<double> operator- (vector<double> a, vector<double> b) { vector<double> ret; for (int i = 0; i < a.size() ; i++) { ret.push_back(a[i] - b[i]); } return ret; } vector<double> sortvect(vector<double> a) { double temp; for (int i = 0; i < a.size() ; i++) { for (int j = a.size()-1 ; j > i; j--) { if (a[i]>a[j]) { temp = a[i]; a[i] = a[j]; a[j] = temp; } } } return a; } vector<double> getrank(vector<double> a) { vector<double> ranks(a.size()); vector<double> b(sortvect(a)); for (int i = 0; i < a.size() ; i++) { for (int j = 0; j < b.size() ; j++) { if (a[i] == b[j]) { ranks.push_back(j); break; } } } return ranks; } int main() { double n; cin >> n; vector<double> x,y; double a; for (int i = 0; i < n; i++) { cin >> a; x.push_back(a); } for (int i = 0; i < n; i++) { cin >> a; y.push_back(a); } vector<double> rankx(getrank(x)); vector<double> ranky(getrank(y)); vector<double> diff(rankx-ranky); double sumds = sumarr(power(diff,2)); cout << fixed << setprecision(3) << 1 - (6 * sumds) / (n*(n*n - 1)); return 0; }