C++語言編程，定步長辛普森公式求積分

/*

n = 3474,s = 0.499822

Press any key to continue

*/

#include?<stdio.h>

int?main()?{

double?a?=?0.0,b?=?0.8;

double?h,ds,s?=?10.0,sum?=?0.0;

double?eps?=?1E-8;

int?i,n?=?1;

while(fabs(sum?-?s)?>?eps)?{

++n;

h?=?(b?-?a)/(2?*?n);

ds?=?0.0;

sum?=?s;

for(i?=?1;?i?<=?2?*?n?-?1;?++i)

ds?+=?2.0?*?cos(a?+?2?*?(i?-?1)?*?h)?+?cos(a?+?2?*?i?*?h);

s?=?(b?-?a)/(3?*?n)?*?(cos(a)?-?cos(b)?+?ds)?/?2.0;?

}

printf("n?=?%d,s?=?%lf\n",n,s);

return?0;

}