如何用Shell来实现一个精彩的算术例子？？？

UltimateSniper

各位大神，昨天见到一个不错的题目，但思前想后没有想出来解法，遂贴出来，希望集思广益，看看大家有没有好的思路或解法：


大家一起探讨探讨，学习咯！

UltimateSniper

@waker
@rdcwayx
@expert1
@Shell_HAT
@zooyo
......

wenhq

找永夜吧！应该能帮你搞定。

代号：军刀

1. [root@ ~]$ awk -vlen=9 'BEGIN{for(i=1;i<=len;i++){for(j=1;j<=i;j++){a=a""j;if(i==j){printf a" * 8 + "i" =" expr a * 8 + i"\n";a=""}}}}'
   
2. 1 * 8 + 1 =9
   
3. 12 * 8 + 2 =98
   
4. 123 * 8 + 3 =987
   
5. 1234 * 8 + 4 =9876
   
6. 12345 * 8 + 5 =98765
   
7. 123456 * 8 + 6 =987654
   
8. 1234567 * 8 + 7 =9876543
   
9. 12345678 * 8 + 8 =98765432
   
10. 123456789 * 8 + 9 =987654321

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代号：军刀

1. [root@ ~]$ awk -vlen=9 'BEGIN{for(i=1;i<=len;i++){for(j=1;j<=i;j++){a=a""j;if(i==j){printf a" * 9 + "expr i + 1" =" expr a * 9 + i + 1"\n";a=""}}}}'
   
2. 1 * 9 + 2 =11
   
3. 12 * 9 + 3 =111
   
4. 123 * 9 + 4 =1111
   
5. 1234 * 9 + 5 =11111
   
6. 12345 * 9 + 6 =111111
   
7. 123456 * 9 + 7 =1111111
   
8. 1234567 * 9 + 8 =11111111
   
9. 12345678 * 9 + 9 =111111111
   
10. 123456789 * 9 + 10 =1111111111

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hbmhalley

1. $ dc -e '0 0[1+dstr10*+dn[ * 8 + ]nltn[ = ]nd8*lt+psrltd9>a]dsax';\
   
2. > dc -e '0 1[d1+str10*+dn[ * 9 + ]nltn[ = ]nd9*lt+psrltd9>a]dsax';\
   
3. > dc -e '0 7[dstr10*2++dn[ * 9 + ]nltn[ = ]nd9*lt+psrlt1-d0!>a]dsax';\
   
4. > dc -e '0 0[1+r10*1+dn[ * ]ndn[ = ]ndd*psrrd9>a]dsax';
   
5. 1 * 8 + 1 = 9
   
6. 12 * 8 + 2 = 98
   
7. 123 * 8 + 3 = 987
   
8. 1234 * 8 + 4 = 9876
   
9. 12345 * 8 + 5 = 98765
   
10. 123456 * 8 + 6 = 987654
    
11. 1234567 * 8 + 7 = 9876543
    
12. 12345678 * 8 + 8 = 98765432
    
13. 123456789 * 8 + 9 = 987654321
    
14. 1 * 9 + 2 = 11
    
15. 12 * 9 + 3 = 111
    
16. 123 * 9 + 4 = 1111
    
17. 1234 * 9 + 5 = 11111
    
18. 12345 * 9 + 6 = 111111
    
19. 123456 * 9 + 7 = 1111111
    
20. 1234567 * 9 + 8 = 11111111
    
21. 12345678 * 9 + 9 = 111111111
    
22. 9 * 9 + 7 = 88
    
23. 98 * 9 + 6 = 888
    
24. 987 * 9 + 5 = 8888
    
25. 9876 * 9 + 4 = 88888
    
26. 98765 * 9 + 3 = 888888
    
27. 987654 * 9 + 2 = 8888888
    
28. 9876543 * 9 + 1 = 88888888
    
29. 98765432 * 9 + 0 = 888888888
    
30. 1 * 1 = 1
    
31. 11 * 11 = 121
    
32. 111 * 111 = 12321
    
33. 1111 * 1111 = 1234321
    
34. 11111 * 11111 = 123454321
    
35. 111111 * 111111 = 12345654321
    
36. 1111111 * 1111111 = 1234567654321
    
37. 11111111 * 11111111 = 123456787654321
    
38. 111111111 * 111111111 = 12345678987654321
    

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ljwd1000

回复 6# hbmhalley


    天书呀

UltimateSniper

回复 4# 代号：军刀


    十分感谢，awk的用处没想到这么大！

UltimateSniper

回复 6# hbmhalley


    强大！之前完全没有听说过 dc 这个工具，这次算是见识了！

yinyuemi

回复 1# UltimateSniper

1. awk 'BEGIN{for(i=1;i<=9;i++){print (t=t i),"*",8,"+",i," = ",t*8+i}}'
   
2. 1 * 8 + 1  =  9
   
3. 12 * 8 + 2  =  98
   
4. 123 * 8 + 3  =  987
   
5. 1234 * 8 + 4  =  9876
   
6. 12345 * 8 + 5  =  98765
   
7. 123456 * 8 + 6  =  987654
   
8. 1234567 * 8 + 7  =  9876543
   
9. 12345678 * 8 + 8  =  98765432
   
10. 123456789 * 8 + 9  =  987654321
    
11. 
    
12. awk 'BEGIN{for(i=1;i<=8;i++){print (t=t i),"*",9,"+",i+1," = ",t*9+(i+1)}}'
    
13. 1 * 9 + 2  =  11
    
14. 12 * 9 + 3  =  111
    
15. 123 * 9 + 4  =  1111
    
16. 1234 * 9 + 5  =  11111
    
17. 12345 * 9 + 6  =  111111
    
18. 123456 * 9 + 7  =  1111111
    
19. 1234567 * 9 + 8  =  11111111
    
20. 12345678 * 9 + 9  =  111111111
    
21. awk 'BEGIN{for(i=9;i>1;i--){print (t=t i),"*",9,"+",i-2," = ",t*9+(i-2)}}'
    
22. 9 * 9 + 7  =  88
    
23. 98 * 9 + 6  =  888
    
24. 987 * 9 + 5  =  8888
    
25. 9876 * 9 + 4  =  88888
    
26. 98765 * 9 + 3  =  888888
    
27. 987654 * 9 + 2  =  8888888
    
28. 9876543 * 9 + 1  =  88888888
    
29. 98765432 * 9 + 0  =  888888888
    
30. [jhou@localhost Dataset Published]$ awk 'BEGIN{for(i=9;i>1;i--){print (t=t 1),"*",(t)," = ",t*t}}'
    
31. 1 * 1  =  1
    
32. 11 * 11  =  121
    
33. 111 * 111  =  12321
    
34. 1111 * 1111  =  1234321
    
35. 11111 * 11111  =  123454321
    
36. 111111 * 111111  =  12345654321
    
37. 1111111 * 1111111  =  1234567654321
    
38. 11111111 * 11111111  =  123456787654321
    

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