/******************************************/
/*                                        */
/*             復(fù)合辛普生                 */
/*                                        */
/******************************************/
#include<stdio.h>
#include<math.h>
#define type "%lf"   /*-數(shù)據(jù)類型-*/
#define epsilon 1e-8
typedef double Dtype;
Dtype f(Dtype x)
{
	return exp(x)*cos(x);
}
Dtype Df3(Dtype x)
{
	return -2*exp(x)*(cos(x)+sin(x));
}

void main()
{
	int k,n;
	Dtype a,b,h,sum,Sn;

	/*-輸入?yún)^(qū)間[a,b]及n等分-*/
	printf("Please input [a,b]:\n");
    scanf(type type,&a,&b);
	/*-利用復(fù)合辛普生公式計(jì)算Sn-*/
	n=1;
	do{
		h=(b-a)/n;
		
		Sn=f(a);sum=0;
		for(k=0;k<=n-1;k++)
			sum+=f(a+k*h+h/2);
		Sn+=4*sum;
		sum=0;
		for(k=1;k<=n-1;k++)
			sum+=f(a+k*h);
		Sn+=2*sum+f(b);
		Sn=Sn*h/6;
		n=n+1;    /*-逐漸增加等分?jǐn)?shù)-*/
	}while(fabs(-1/(double)180*pow((h/2),(double)4)*(Df3(b)-Df3(a)))>epsilon);
   printf("n=%d,Sn="type,n-1,Sn);
}