number of permutations in c language

Question

hi friend,

     

           When not in use the system to provide built-in function to achieve full array in c language.

Such as:

Please input n=3

123

132

213

231

312

321

Please input n=4

1234

1243

1324

1342

1423

1432

2134

2143

2314

2341

2413

2431

3124

3142

3214

3241

3412

3421

4123

4132

4213

4231

4312

4321

thanks.