java質數 哪邊出錯無法增加逗號

Question

如何把質數後面加逗號，
並且每10個質數換行，
還有全部質數加起來有幾個。
幫修改拜託哩~~


import java.util.*;

public class Prime {

public static int[] findPrimes(final int max) {
int[] prime = new int[max+1];
ArrayList list = new ArrayList();

for(int i = 2; i <= max; i++)
prime[i] = 1;

for(int i = 2; i*i <= max; i++) { // 這邊可以改進
if(prime[i] == 1) {
for(int j = 2*i; j <= max; j++) {
if(j % i == 0)
prime[j] = 0;
}
}
}

for(int i = 2; i < max; i++) {
if(prime[i] == 1) {
list.add(new Integer(i));
}
}

int[] p = new int[list.size()];
Object[] objs = list.toArray();
for(int i = 0; i < p.length; i++) {
p[i] = ((Integer) objs[i]).intValue();
}

return p;
}

public static void main(String[] args) {
int[] prime = Prime.findPrimes(100);

int sum = 0;
for(int i = 0; i < prime.length; i++) {
System.out.print(\\nprime[i] + " ");
sum = sum + prime[i];
}

System.out.println("\\n總和：" + sum);
}
}

Answer 1

你的 findPrimes 方法寫得不錯，不需要再改了。所以我僅就你想要的 10 個質數換行以及印出總個數來更改 main 方法，請參考我的寫法。 public static void main(String[] args) {  int[] prime = Prime.findPrimes(100);    int sum = 0;  int flag = 1;  for(int i = 0; i < prime.length; i++, flag++) {   if (flag == 1) {    System.out.print("" + prime[i]);   } else if (flag <= 9) {    System.out.print(", " + prime[i]);   } else {    flag = 0;    System.out.println(", " + prime[i]);   }   sum = sum + prime[i];  }  System.out.println();  System.out.println("總和：" + sum);  System.out.println("個數: " + prime.length); }

Answer 2

那是...抄良葛格網站的吧?