试位法求解非线性方程

//用试位法求解非线性方程

#include <iostream>

#include <math.h>

#include <process.h>

using namespace std;

class falsi

{

private:

int iteration;

double eps, error, f, f_low, f_high, f_new, x_low, x_high, x_new;

double d, fric, Q, s, W;

public:

falsi()

{

iteration = 0;

fric = 0.01;

Q = 10;

s = 1e-3;

W = 10;

}

void solution();

double function(double d)

{

double term1 = d * pow((W * d / (W + 2 * d)), (2.0 / 3.0));

double term2 = fric * Q / (W * sqrt(s));

f = term1 - term2;

return f;

}

};

void main()

{

falsi regula;

regula.solution();

}

void falsi::solution()

{

cout << "\n输入下限：";

cin >> x_low;

cout << "\n输入上限：";

cin >> x_high;

f_low = function(x_low);

f_high = function(x_high);

if ((f_low * f_high) > 0)

{

cout << "\n错误的归类。" << endl;

exit(0);

}

cout << "\n输入公差：";

cin >> eps;

do

{

iteration++;

x_new = (x_low * f_high - x_high * f_low) / (f_high - f_low);

f_new = function(x_new);

error = fabs(f_new);

if ((f_new * f_low) < 0)

{

x_high = x_new;

}

else

{

x_low = x_new;

f_low = f_new;

}

}while (error >= eps);

cout << "\n解是：" << x_new << endl;

cout << "\n收敛于" << iteration << "次迭代" << endl;

}