有1、2、3、4个数字，能组成多少个互不相同且无重复数字的三位数？都是多少？

1.程序分析：可填在百位、十位、个位的数字都是1、2、3、4。组成所有的排列后再去

　　　　　　 掉不满足条件的排列。

-There 1,2,3,4 numbers, how many can be formed from each other and without duplication of the three-digit numbers? How many are? 1. Program Analysis: You can fill in the 100, 10, and one-bit numbers are 1,2,3,4. Composed of all of the array and then get rid of the arrangement does not meet the conditions.