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5_least-square-method.cpp
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5_least-square-method.cpp
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#include <bits/stdc++.h>
using namespace std;
class Least_Square_Method {
private:
int size;
double x[100], y[100];
// y = ax + b
double a, b, xSum, ySum, xySum, xxSum;
public:
void fit_the_curve() {
cout << "Number of points: ";
cin >> size;
cout << "Enter " << size << " points: " << endl;
for(int i = 0; i<size; i++) {
cin >> x[i] >> y[i];
}
xSum = ySum = xySum = xxSum = 0.0;
for(int i = 0; i<size; i++) {
xSum += x[i];
ySum += y[i];
xxSum += x[i] * x[i];
xySum += x[i] * y[i];
}
a = (size * xySum - xSum * ySum) / (size * xxSum - xSum * xSum);
b = (ySum - a * xSum) / size;
cout << "The value of a = " << a << endl;
cout << "The value of b = " << b << endl;
cout << fixed << setprecision(4) << "Y = " << a << "x + " << b << endl;
}
};
int main() {
Least_Square_Method lscf;
lscf.fit_the_curve();
return 0;
}
/*
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Y = 0.1879x + 2.276
*/