急求java中求定积分的程序，急啊！！后天就要考试了！！

定积分

import static java.lang.Math.*

public class homeworkfour {

// 0~1区间n等分

private static int n = 100000

// 随便定义个曲线e的x次方, 取其x在0~1的定积分

public static double f(double x) {

double f

f = pow(E, x)

return f

}

// 梯形法求定积分

/**

* x0: 坐标下限, xn: 坐标上限

*/

public static double getDefiniteIntegralByTrapezium(double x0, double xn) {

double h = abs(xn - x0) / n

double sum = 0

for (double xi = 0xi <= xnxi = xi + h) {

sum += (f(xi) + f(xi + h)) * h / 2

}

return sum

}

/**

* x0: 坐标下限, xn: 坐标上限

*/

// 矩形法求定积分, 右边界

public static double getDefiniteIntegralByRectangle1(double x0, double xn) {

//h: 步长

double h = abs(xn - x0) / n

double sum = 0

for (double xi = 0xi <= xnxi = xi + h) {

sum += f(xi + h) * h

}

return sum

}

// 矩形法求定积分, 左边界

public static double getDefiniteIntegralByRectangle2(double x0, double xn) {

double h = abs(xn - x0) / n

double sum = 0

for (double xi = 0xi <= xnxi = xi + h) {

sum += f(xi) * h

}

return sum

}

/**

* 测试定积分

*/

public static void main(String[] args) {

System.out.println(getDefiniteIntegralByTrapezium(0, 1))

System.out.println(getDefiniteIntegralByRectangle1(0, 1))

System.out.println(getDefiniteIntegralByRectangle2(0, 1))

}

}

思路：利用for循环判断是否是奇数，如果是累计，最后输出累加和。

参考代码：

#include "stdio.h" 

int main() 

{ 

int i,sum=0

for(i=1i<=15i++)

if(i%2) sum+=i

printf("%d\n",sum)

return 0

}

/*

运行结果：

64

*/

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