多项式拟合+高斯消元解方程组

#include<iostream>
#include<cmath>
#include<vector>
using namespace std;
void func(float**p,float *q,float *r,int n)
{
	//Gauss消元
	int i,j,k,t;
	for(i = 0;i<n-1;i++)
	{
		//选主元模块 顺序gauss消元可不要
		int tmp = i;
		float max = fabs(p[i][i]);
		for(t = i+1;t<n;t++)
		{
			if(fabs(p[t][i]) > max)
				tmp = t;
		}
		for(t = i;t<n;t++)
		{
			float tmp2 = p[i][t];
			p[i][t] = p[tmp][t];
			p[tmp][t] = tmp2;
		}
		float tmp3 = q[i];
		q[i] = q[tmp];
		q[tmp] = tmp3;
		if(p[i][i] == 0)
		{
			cout<<"gauss消元失败"<<endl;
			return;
		}
		//消元模块
		for(j = i+1;j<n;j++)
		{
			for(k = i+1;k<n;k++)
			{
				p[j][k] = -p[j][i]*1.0/p[i][i]*p[i][k] + p[j][k];
			}
			q[j] = -p[j][i]*1.0/p[i][i]*q[i] + q[j]; 
		}
	}
	//回带模块
	r[n-1] = q[n-1]*1.0/p[n-1][n-1];
	for(i = n-2;i>=0;i--)
	{
		float tmp = 0.0;
		for(j = i+1;j<n;j++)
		{
			tmp+= p[i][j]*r[j];
		}
		r[i] = (q[i]-tmp)*1.0/p[i][i];
	}
}
int main()
{
	int m;
	cout<<"输入拟合多项式的次数"<<endl;
	while(cin>>m && m != -1)
	{
		//m次多项式曲线
		int sum = 0,i,j,k;
		cout<<"输入x和y的有序对 x=0&&y=0时输入结束"<<endl;
		vector<float>x,y;
		float x0,y0;
		while(cin>>x0>>y0 && !(x0 == 0 && y0 == 0))
		{
			x.push_back(x0);
			y.push_back(y0);
			sum ++;
		}
		float **p = new float*[m+1];
		float *q = new float[m+1];
		float *r = new float[m+1];
		for(i = 0;i<m+1;i++)
			p[i] = new float[m+1];
		for(i = 0;i<m+1;i++)
		{
			for(j = 0;j<m+1;j++)
			{
				float tmp = 0.0;
				for(k = 0;k<sum;k++)
				{
					tmp += pow(x[k],i+j);
				}
				p[i][j] = tmp;
			}
		}
		for(i = 0;i<m+1;i++)
		{
			float tmp = 0.0;
			for(j = 0;j<sum;j++)
			{
				float tmp2 = pow(x[j],i);
				tmp += y[j]*tmp2;
			}
			q[i] = tmp;
		}
		cout<<m<<"次多项式系数为"<<endl;
		func(p,q,r,m+1);
		for(i = 0;i<m+1;i++)
		{
			cout<<r[i]<<" ";
		}
		cout<<endl;
		cout<<"输入拟合多项式的次数"<<endl;
	}
	return 0;
}