冒泡排序

 int[] nums = {3,1,-2,7,5};
    //如果一轮比较后没有发生转化，说明已经排序好了，停止循环
    boolean flag = false;
    for (int i = 0; i < nums.length - 1; i++) {
      for (int j = 0; j < nums.length -1 - i; j++) {
        if (nums[j] > nums[j + 1]) {
          flag = true;
          int temp = nums[j];
          nums[j] = nums[j + 1];
          nums[j + 1] = temp;
        }
      }
      if (!flag) {
        break;
      } else {
        flag = false;
      }
      System.out.println("第" + (i + 1) + "次排序的结果");
      System.out.println(Arrays.toString(nums));
    }