lagrange interpolation method.txt

朗格朗日插值计算可以方便快捷的生成计算程序

#include "stdafx.h"
#include <iostream>	
#include <iomanip>
using namespace std;
//-----------gcc函数的定义-------------------
double gcc( double a[][40],double w,int m)
{
	int i,j;
	double s=0,x;
	for (i=0;i<m;i++)
	{
		x=1;
		for(j=0;j<m;j++)
			if (j!=i)
			{
                x*=(w-a[0][j])/(a[0][i]-a[0][j]);
			}
		s+=x*a[1][i];
	}
	
	return s;
}
int _tmain(int argc,_TCHAR* argv[] )
{
	int i,j,m;
	double a[2][40]={0},w;
	cout <<"请输入点的个数："<<endl;
	cout <<"m=";
	cin >> m;
	cout <<endl;
	cout << "请输入函数矩阵：" <<endl;
	for (i=0;i<2;i++)
		for (j=0;j<m;j++)
			cin >>a[i][j];
	cout <<"请输入w的值：" <<endl;
	cout <<"w=";
	cin >>w;
	for (i=0;i<2;i++)
	{
		for (j=0;j<m;j++)
			cout<<setw(5)<<a[i][j];
	        cout <<endl;
	}
	cout <<"您输入的点的坐标为："<< "( "<<w<<","<<gcc(a,w,m)<<" )"<<endl;
	cin>>i;
	return 0;

}