JAVA经典基础练习题及参考答案.pdf

1. 写一个函数，计算一个整数数组的平均值 import java.util.Random; public class javaSevenDayLianXi public static void main(String args) int arr = new int10; Random score = new Random(); float sum = 0.0f; System.out.print(“这组数为:“); for (int i = 0; i 0) System.out.print(term + “ “); public static void insert(int pos, int value) int arrays; if (index = arr.length) arrays = new intindex + 1; System.arraycopy(arr, 0, arrays, 0, index); else arrays = arr; System.arraycopy(arrays, pos, arrays, pos + 1, index - pos); arrayspos = value; index+; for (int term : arrays) if (term 0) System.out.print(term + “ “); 7. *完成数组的冒泡排序算法：给定一个数组：int a = 1,3,2,7,5，利用冒泡排序对其按照 从小到大的顺序排序，然后输出结果。 public class javaSevenDayLianXi public static void main(String args) int arr = 1, 3, 2, 7, 5 ; int term = 0; for (int i = 0; i arrj) term = arrj; arrj = arri; arri = term; System.out.print(“按冒泡排序后的结果为:“); for (int i : arr) System.out.print(i + “ “); 8. *使用第二种算法对数组进行排序 import java.util.Arrays; public class javaSevenDayLianXi public static void main(String args) int arr = 1, 3, 2, 7, 5 ; Arrays.sort(arr); System.out.print(“用第二种方法给数组排序后的结果为:“); for (int i : arr) System.out.print(i + “ “); 杨辉三角的特点： 1. 第i 行有i 个元素 2. 每一行的第一个元素和最后一个元素都为1 3. 除了1 之外，每个元素的值，都等于上一行同位置的元素以及前一个元素的和。 例如： 1 4 6 4 1 的下一行 1 a1 a2 a3 a4 1 a1 = 4 + 1 = 5 a2 = 6 + 4 = 10 a3 = 4 + 6 = 10 a4 = 1 + 4 = 5 依次类推。 要求：读入一个整数n，输出杨辉三角的前n 行 import java.util.Scanner; public class javaSevenDayLianXi public static void main(String args) Scanner sca = new Scanner(System.in); System.out.print(“请输入杨辉三角的行数:“); int row = sca.nextInt(); int arr = getArrays(row); for (int a : arr) for (int term : a) System.out.print(term 0 ? term : “)+ “); System.out.println(); public static int getArrays(int row) int arr = new introwrow; for (int i = 0; i = 1000 listSub = 0; else if (rowSub 0 else start = up; rowSub-; break; case up: if (rowSub circle) rowSub-; else circle+; start = right; listSub+; break; for