みなさん、ここに私のコードがあります：
package Chapter5;
import java.util.Scanner;
public class MainMenu extends Integration
{
static Scanner s = new Scanner(System.in);
static int c;
static double lower, upper;
static double Curves;
static double sum = 0;
public static void main(String[] args)
{
while(true)
{
System.out.println("Please choose one of the options");
System.out.println("1: Calculate the area between two curves");
System.out.println("2: Calculate the volume when two curves are revolved about a disk");
System.out.println("3: Calculate the volume when a single curve is revolved about a shell");
System.out.println("4: Quit");
c = s.nextInt();
if(c == 1)
{
System.out.println("Area between two curves");
System.out.println("Please enter the lower limit");
lower = s.nextInt();
System.out.println("Please enter the upper limit");
upper = s.nextInt();
System.out.print("Lower limit: " + lower);
System.out.println(" Upper limit: " + upper);
System.out.println("The area under the f curve: " + sumf);
System.out.println("The area under the g curve: " + sumg);
sum = sumf - sumg;
System.out.println("Area between the two curves = " + sum);
}
if(c == 2)
{
System.out.println("Working");
}
if(c == 3)
{
System.out.println("Working");
}
if(c == 4)
{
break;
}
}
}
ここに私の統合クラスがあります:
package Chapter5;
/*Author: Cory Zander
* Purpose: Find the area and volume between two curves
*/
public class Integration
{
static double x;
static double dx;
static double f, g;
static double sumg = 0;
static double sumf = 0;
public static double f(double x)
{
f = x * Math.exp(x);
return x;
}
public static double g(double x)
{
g = Math.pow(x, 2);
return x;
}
public static double Areaf(double lower, double upper)
{
int i;
x = lower;
dx = (upper - lower)/2000;
for(i = 0; i <= 2000; i++)
{
if(i == 0 || i == 2000)
{
sumf += f;
}
else
{
sumf += 2 * f;
}
x += dx;
}
sumf *= dx/2;
return sumf;
}
public static double Areag(double lower, double upper)
{
int i;
x = lower;
dx = (upper - lower)/2000;
for(i = 0; i <= 2000; i++)
{
if(i == 0 || i == 2000)
{
sumg += g;
}
else
{
sumg += 2 * g;
}
x += dx;
}
sumg *= dx/2;
return sumg;
}
さて、これを編集して、面積と面積の問題を修正しましたが、何らかの理由で、f 曲線の下の面積を取得すると、まだ 0 になります。統合クラスから sumf を取得しないのはなぜですか