public class Demo {

  /**
    *列出100以内的素数(质数)
    */
  public static void main(String[] args) {

    String s = "100以内的素数：";
    for (int i = 1; i <= 100; i++) {
      int count = 0;
      for (int j = 1; j <= (int) Math.sqrt(i); j++) {
        // Math.sqrt(i)对i开方
        if (i % j == 0)// 若被整除
          count++;
      }
      if (count > 1) {
//count > 1证明都不是质数
        s += "";
      } else {//证明第i个数是质数
        s += i + " ";
      }
    }
    System.out.println(s);
  }

}