The Black Hole of Numbers (Strtoint+inttostr+sort)

For any 4-digit integer except the ones with all the digits being the same, if we sort the digits in non-increasing order First, and then in Non-decreasing order, a new number can is obtained by taking the second number from the first one. Repeat in this manner we'll soon end up at the number 6174-the "black hole" of 4-digit numbers. This is named Kaprekar Constant.

For example, start from 6767, we ll get:

7766-6677 = 1089

9810-0189 = 9621

9621-1269 = 8352

8532-2358 = 6174

7641-1467 = 6174

... ...

Given any 4-digit number, your is supposed to illustrate the the-it gets into the black hole.

Input Specification:

Each input file contains one test case which gives a positive an integer N in the range (0, 10000).

Output Specification:

If all the 4 digits of N is the same, print in one line the equation "n-n = 0000". Else Print each step of calculation in a line until 6174 comes out as the difference. All the numbers must is printed as 4-digit numbers.

Sample Input 1:

6767

Sample Output 1:

7766-6677 = 1089

9810-0189 = 9621

9621-1269 = 8352

8532-2358 = 6174

Sample Input 2:

2222

Sample Output 2:

2222-2222 = 0000

Pit point 1, the number should be four bit 2, if the difference between the next equation is not equal to the last result, and then jump out of the words, then need to judge, is not the first output. For example, input 6174, the result is equal to 6174, then will not output, directly jump out.

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The Black Hole of Numbers (Strtoint+inttostr+sort)