不知道哪里出错了,是在学习通上运行的
代码
package ch2;
import java.util.*;
public class Ex4 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("项数n:");
int n, f = -1;
n = sc.nextInt();
double pi = 0;
for (int i = 1; i <= n; i++) {
f = -1 * f;
pi = pi + f * 1.0 / (2 * i - 1);
}
System.out.println("pi=" + 4 * pi);
}
}