six.cpp

这是我数值分析课程的实习题目的源代码(并附有文档),文档包括对问题进行了描述,并对结果进行分析,希望对大家有所帮助.

#include <iostream.h>
#include<math.h>
#include<iomanip.h>
double Funtion (double c);
double Funtion1(double x);

main()
{

	//二分法
	double a=0,b=1;
	double x=0.3604217;
	double h=0;
	int n=0;
	do{
		 h=(a+b)/2;
		if(Funtion(a)*Funtion(h)<0)
			b=h;
		if(Funtion(h)*Funtion(b)<0)
			a=h;
		n++;

	}while(fabs(h-x)>0.00001);
		cout<<setprecision(12)
			<<"the answer is:"<<h<<endl<<"the count is:"<<n<<endl;
	//牛顿法
		double x1[40];
		x1[0]=1;
		int n1=0;
		do{
			x1[n1+1]=x1[n1]-Funtion(x1[n1])/Funtion1(x1[n1]);
			n1++;
			
		}while(fabs(x1[n1]-x1[n1-1])>0.00001);
		cout <<setprecision(12)
			<<"the answer is:"<<x1[n1]<<endl<<"the count is:"<<n1<<endl;
	//弦截法
		double x2[40];
		x2[0]=0;
		x2[1]=1;
		int n2=0;
		do{
			x2[n2+2]=x2[n2]*Funtion(x2[n2+1])
				/(Funtion(x2[n2+1])-Funtion(x2[n2]))
				+x2[n2+1]*Funtion(x2[n2])
				/(Funtion(x2[n2])-Funtion(x2[n2+1]));
			n2++;

		}while(fabs(x2[n2+1]-x2[n2])>0.00001);
		cout <<setprecision(12)
			<<"the answer is:"<<x2[n2+1]<<endl<<"the count is:"<<n2<<endl;


			

	return  0;
}
//函数
double Funtion (double x)
{
	return 3*x+sin(x)-exp(x);
}

//函数的导数
double Funtion1(double x)
{
	return 3+cos(x)-exp(x);
}
//
/*
the answer is:0.360412597656
the count is:14
the answer is:0.36042170296
the count is:5
the answer is:0.360421702961
the count is:6
Press any key to continue
*/