编写程序验证6174猜想，要求使用函数。6174猜想的内容大致为：任意一个大于1000的4位数，若每位不全部相等，经过最多7次K变换可以变为6174。K变换是把4位数从大到小重新排列减去从小到大重新排列并求值。如：4948

1: 9844 - 4489 = 5355

2: 5553 - 3555 = 1998

3: 9981 - 1899 = 8082

4: 8820 - 288 = 8532

5: 8532 - 2358 = 6174-Write a program 6174 conjecture, validation request use function. The content of 6174 guess roughly include: any more than 1,000 4 digits, if each not all equal, after seven times most commutation can become 6174 K. K transform is sending four digits from large to small rearrange minus childhood rearrange and evaluated. Such as: 4948

1:9844-4489 = 5355

2:　　5553- 3555 = 1998

3:　　9981- 1899 = 8082

4:　　8820- 288 = 8532

5:　　8532- 2358 = 6174