dttx.cpp

这是递推梯形的源代码

/*该程序功能:完成计算方法书67页递推梯形法的流程图算法,针对67页例3*/
                         #include "stdafx.h"
                            #include<iostream.h>
                                #include<math.h>
                                  #include<stdio.h>
double f(double x)
{
	return sin(x)/x;
}
int main(int argc, char* argv[])
{
	int n=1;
	double a,b,c,h,T1,x,T2,S,flag;
	   cout<<"Please enter 3 number:"<<endl;
	     cin>>a>>b>>c;  
	        h=b-a;
			  flag=0;
      T1=h*(1+f(b))/2;
	  
	do
	{
		if(flag)
		{
			h=h/2;
			  T1=T2;
		}
		flag=1;
		    S=0;
		      x=a+h/2;
		do{
			S+=f(x);
			     x+=h;
		}
		while(x<b);
		     T2=T1/2+h*S/2;
			 n=n*2;
	}
	 while(fabs(T2-T1)>=c);
	   cout<<"结果是:"<<endl;
	     cout<<"n="<<n<<endl;
		 printf("变步长梯形法求积值为:%.7f\n",T2);
 	return 0;
}