code : https://github.com/lujinjianst/myNCCL/blob/master/exercise/exercise-14.5.c
computational results :
[haoyue@centos exercise]$ ./a.out
enter squqre n(ODD) number:3
8 1 6
3 5 7
4 9 2
[haoyue@centos exercise]$ ./a.out
enter squqre n(ODD) number:5
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
10 12 19 21 3
11 18 25 2 9
[haoyue@centos exercise]$ ./a.out
enter squqre n(ODD) number:7
30 39 48 1 10 19 28
38 47 7 9 18 27 29
46 6 8 17 26 35 37
5 14 16 25 34 36 45
13 15 24 33 42 44 4
21 23 32 41 43 3 12
22 31 40 49 2 11 20