Question

怎样用java打印杨辉三角，自己输入行

Answer 1

/**
* 打印杨辉三角
功能描述：使用多重循环打印6阶杨辉三角
* @author pieryon
*
*/
public class YHSJ {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("请输入行号：");
int m = in.nextInt();
int n = 2*m-1;//列元素数；
int arr[][] = new int[m][n];
for (int i = 0; i < m; i++) { //外循环控制行
for (int j = 0; j < n; j++) { //内循环控制列
if (j<(m-i-1)||(j>=(m+i))) { //输出等腰三角形两边空格
System.out.print(" ");

}else if (j==(m-i-1)||j==(m+i-1)) { //计算输出等腰三角形两边的空格
arr[i][j] = 1;
System.out.print(arr[i][j]);
}else if ((i+j)%2==0&&m%2==0||(i+j)%2==1&&m%2==1) {
System.out.print(" ");
}else {
arr[i][j] = arr[i-1][j-1]+arr[i-1][j+1];
System.out.print(arr[i][j]);
}
}
System.out.println();
}
}
}
以上就可以轻松实现杨辉三角的打印了！

Answer 2

//用递归做

import java.util.Scanner;
public class 杨辉三角 {
/**
* @param args
*/
private static int fun(int i, int j) {
// TODO Auto-generated method stub
if(j == 0 || j == i+ 1 )
return 1;
else
return fun(i - 1, j - 1)+ fun(i - 1, j);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc = new Scanner(System.in);
System.out.println("请输入行数：");
int n = sc.nextInt();
int i = 0,j = 0;
for(i = 0; i <= n+1; i++)
System.out.print(" ");
System.out.println(1
);
for(i = 0; i < n; i++)
{
for(j = 0; j < n - i; j++)
System.out.print(" ");
for(j = 0; j < i+ 2; j++)
System.out.print(" "+fun(i,j));
System.out.println();
}
}
}

//可以打印任意行数

Answer 3

将循环条件改成动态的就可以啦！