#include
typedef double Fun(double x);
double integral(Fun f,double x1,double x2,int n)
{
double delta = (x2 - x1) / n;
double I = 0.5 * (f(x1) + f(x2))* delta;
int i = 1;
for( ; i < n; i++)
I += f(x1 + delta * i)* delta;
return I;
}
double fun(double x)
{
return x * x;
}
int main()
{
double a,t,ret;
int n;
printf("输入积分左右端点a,t,梯形个数n\n");
scanf("%lf %lf %d",&a,&t,&n);
ret = integral(fun,a,t,n);
printf("x^2在[%lf,%lf]上的定积分为%lf\n",a,t,ret);
return 0;
}
运行结果
输入积分左右端点a,t,梯形个数n
0 1 2000
x^2在[0.000000,1.000000]上的定积分为0.333333
