C语言:利用指针编写程序,用梯形法计算给定的定积分实例

double(*pfunction)() = &function;

#include <stdio.h>#include <math.h>double function(double x){  return (double)(pow(x,3) + x/2 + 1);}double calc(double a, double b){  double ha, hb, result=0;  int i;  double(*pfunction)() = &function;   for(i=0; i<1000; i++){    ha = (*pfunction)(a+i*(b-a)/1000.0);    hb = (*pfunction)(a+(i+1)*(b-a)/1000.0);    result += ((ha + hb)*(b-a)/1000.0)/2.0;  }  return result;}void main(){  double a = 0, b = 10, result;  result = calc(a, b);  printf("%lf", result);}

2535.002500