Java基础3

1

//输出杨辉三角

import java.util.Scanner;public class Hello {public static void main(String args[]){Scanner sc = new Scanner(System.in);int n = sc.nextInt();int[][] arr = new int[n][n];for(int x=0;x<n;++x){arr[x][0] = 1;arr[x][x] = 1;}for(int i=2;i<n;i++)for(int j=1;j<=i-1;++j){arr[i][j] = arr[i-1][j-1] + arr[i-1][j];}for(int i=0;i<n;i++){for(int j=0;j<=i;j++){System.out.println(arr[i][j]+"\t");}System.out.println();}}}

2 

public class Hello {public static void main(String args[]){int a = 3, b = 4;System.out.println(a+","+b);change(a, b);// 4 3System.out.println(a+","+b);// 3 4int[] arr = new int[]{1,2,3,4};for(int i=0;i<arr.length;i++){System.out.println(arr[i]+" ");}System.out.println();changeArr(arr);//1 4 3 8for(int i=0;i<arr.length;i++){System.out.println(arr[i]+" ");//1 4 3 8}System.out.println();}public static void change(int a, int b){int temp = a;a = b;b = temp;System.out.println(a+","+b);}public static void changeArr(int[] arr){for(int i=0;i<arr.length;i++){if(arr[i]%2 == 0){arr[i] *= 2;}}for(int i=0;i<arr.length;i++){System.out.println(arr[i]+" ");}System.out.println();}}