杨辉三角正反顺序

正序：

/*方法一写顺

for (i = 0; i < 9; i++) {/*边缘为1*

arr2[i][0] = 1;

arr2[i][i] = 1;

}

for (i = 2; i < 10; i++) {

for (j = 1; j < i;j++)

arr2[i][j] = arr2[i - 1][j - 1] + arr2[i - 1][j];

}*/

/*方法二写顺*/

printf("请输入n=");

scanf("%d", &n);

for (i = 0; i < n; i++){

for (j = n; j >= i; j--)

printf("%2c", ' ');

for (j = 0; j<=i; j++) {

if (j == i||j == 0)

arr1[i][j] = 1;

else

arr1[i][j] = arr1[i-1][j-1] + arr1[i-1][j];

printf("%4d", arr1[i][j]);

if (i == j)

printf("\n");

 }

}

逆序：

/*逆序*/

for (i = n-2; i >= 0;i--) {

for (j = n; j >= i; j--)

printf("%2c", ' ');

for (j = 0; j <= i; j++) {

printf("%4d", arr1[i][j]);

if (i == j)

printf("\n");

}

}

system("pause");

return 0;

}