59.c

计算概论阅读材料

#define PI 3.1415926
#include <math.h>
#include <stdio.h>
void main(void)
{
	double a,b,h,s0,s,x,t1,ept;
	int i,j,n=1;
	scanf("%lf",&ept);
//	scanf("%f",&ept);
	a=PI/4;
	b=PI/2;
	h=(b-a)/n;
	t1=0.5*(sin(a)+sin(b));
	s=t1*h;
	do{
		s0=s;
		n+=n;
		h=h/2;
		x=a+h;
		for(i=1;i<=n/2;i++){
			t1=t1+sin(x);
			x=x+2*h;
			}
		s=t1*h;
	}while(fabs(s-s0)>ept);
	printf("%d%15.10lf\n",n,s);
}