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。 -1, 2, 3, 4 numbers can be composed of a number of three-digit different from each other and no duplication of digital? Are how many?

A program analysis: can fill in one hundred and ten digit figures are 1, 2, 3, 4. Composed of all the permutations and then go

Out does not meet the conditions of the arrangement.