Method_Prost_Iter

#include <cmath>
#include <iomanip>
#include <iostream>
using namespace std;

double f1(double x1, double x2, double x3);
double f2(double x1, double x2, double x3);
double f3(double x1, double x2, double x3);

double g1(double x1, double x2, double x3);
double g2(double x1, double x2, double x3);
double g3(double x1, double x2, double x3);

double f1(double x1, double x2, double x3) {
	return 4 * x1 - x2 - x3 - 6;
}
double f2(double x1, double x2, double x3) {
	return -x1 + 8 * x2 - 4;
}
double f3(double x1, double x2, double x3) {
	return x1 - x2 + 6 * x3;
}
double g1(double x1, double x2, double x3) {
	return x1 - 0.005*f1(x1, x2, x3);
}
double g2(double x1, double x2, double x3) {
	return x2 - 0.005*f2(x1, x2, x3);
}
double g3(double x1, double x2, double x3) {
	return x3 - 0.005*f3(x1, x2, x3);
}

int main()
{
	setlocale(LC_ALL, "Russian");
	cout << "\tВведите матрицу\n";
	double x1; cout << "b1 = "; cin >> x1;
	double x2; cout << "b2 = "; cin >> x2;
	double x3; cout << "b3 = "; cin >> x3;
	double er; cout << "Погрешность = "; cin >> er;
	for
		(
			double it = 1;
			er < fabs(f1(x1, x2, x3)) || er < fabs(f2(x1, x2, x3)) || er < fabs(f3(x1, x2, x3));
			it = it + 1
			)
	{
		system("cls");
		cout << "Иттерация # " << setprecision(0) << it << endl;
		cout << "x1 " << setprecision(0) << (x1 = g1(x1, x2, x3)) << endl;
		cout << "x2 " << setprecision(0) << (x2 = g2(x1, x2, x3)) << endl;
		cout << "x3 " << setprecision(0) << (x3 = g3(x1, x2, x3)) << endl;
	}
	cout << "f1(x1, x2, x3) = 4*x1 - x2 - x3 - 6 = " << f1(x1, x2, x3) << endl;
	cout << "f2(x1, x2, x3) =  -x1 + 8*x2    - 4 = " << f2(x1, x2, x3) << endl;
	cout << "f3(x1, x2, x3) = x1 - x2 + 6*x3     = " << f3(x1, x2, x3) << endl;
	system("pause");
	return 0;
}
/*
1 1 1
*/