新人求教：：关于LOOP和CASE的问题

afton

刚开始自学script，现在刚学到LOOP

在书上看到一个题目，对于CASE不是很会，请高手指点一下

题目是：
  * Accepts two positive integers from the command line. Verify that both arguments were positive integers.  Enclose this verification inside a loop so that if one of these arguments was not a number it would display a "USAGE" error message and then ask the user for proper input. You should remain in this loop until the user data entry is two positive numbers.
          * Prompts the user through a menu, to select a letter that performs one of the following through a case statement:
              1. Display the sum of the two numbers.
              2. Display the product of the two numbers.
              3. State whether the two individual numbers are ODD or EVEN.
              4. Display the higher of the two numbers
              5. Ask the user if they like the "first" or "second" number best (have them input the word) and output "I agree" (if "first") or "I disagree", based on their choice.
              6. Quit the script (Exit)
          * Prints a friendly message if one of the above 5 choices are not chosen correctly (a, b, c, d or e).

justlooks

作业要自己做

afton

因为是自学没有老师指点，所以才来问呀

yinyuemi

可以先自己写个，然后拿出来大家一起讨论

afton

1. #!/bin/bash
   
2. clear
   
3. 
   
4. 
   
5. until echo $1 | grep -s "^[-+]*[0-9][0-9]*$" && echo $2 | grep -s "^[-+]*[0-9][0-9]*$"
   
6. do
   
7.   echo "USAGE:You have selected an INVALID integer."
   
8.   echo "Please re-enter these two positive integers, seperated by sapce: "
   
9. done
   
10. 
    
11. echo
    
12. 
    
13. # Menu Items and prompt user
    
14. 
    
15. 
    
16. cat <<+
    
17. MENU
    
18. a. Display the sum of the two numbers.
    
19. b. Display the product of the two numbers.
    
20. c. State whether the two individual numbers are ODD or EVEN.
    
21. d. Display the higher of the two numbers
    
22. e. Select the number which you like
    
23. f. Quit the script (Exit)
    
24. +
    
25. 
    
26. # Menu Items and prompt user
    
27. 
    
28. read -p "Please select options(a,b,c,d,e or f):" choice
    
29. until [ $choice = "a" ] || [ $choice = "b" ] || [ $choice = "c" ] || [ $choice = "d" ] || [ $choice = "e" ] || [ $choice = "f" ]
    
30. do
    
31. clear
    
32. echo
    
33. cat <<+
    
34. MENU
    
35. a. Display the sum of the two numbers.
    
36. b. Display the product of the two numbers.
    
37. c. State whether the two individual numbers are ODD or EVEN.
    
38. d. Display the higher of the two numbers
    
39. e. Select the number which you like
    
40. f. Quit the script (Exit)
    
41. +
    
42. read -p "Please select options(a,b,c,d,e or f):" choice
    
43. done
    
44. 
    
45. case $choice in
    
46. "a") echo "$1 + $2 = $(($1+$2))"
    
47.      ;;
    
48. "b") echo "$1 * $2 = $(($1*$2))"
    
49.      ;;
    
50. "c") if  test $(($1 %2)) -eq 0
    
51.        then
    
52.            echo "$1 is an EVEN number."
    
53.      else
    
54.          echo "$1 is an ODD number."
    
55.      fi
    
56. 
    
57.      if  test $(($2 % 2)) -eq 0
    
58.         then
    
59.            echo "$2 is an EVEN number."
    
60.      else
    
61.          echo "$2 is an ODD number."
    
62.      fi
    
63.      ;;
    
64. "d") if test $(($1 - $2)) -gt 0
    
65.         then
    
66.            echo "$1 is higher."
    
67.      elif test $(($1-$2)) -eq 0
    
68.         then
    
69.            echo "These two numbers are equal."
    
70.      else
    
71.            echo "$2 is higher."
    
72.      fi
    
73.      ;;
    
74. "e") echo
    
75.      read -p "Do you like the first number or second number best (enter "first" or "second")? : " like
    
76.      until [ $like = "first" ] || [ $like = "second"  ]
    
77.      do
    
78.      read -p "Do you like the first number or second number best (enter "first" or "second")? : " like
    
79.      done
    
80.      if test $like = "first"
    
81.         then
    
82.            echo "I agree."
    
83.      else
    
84.         echo "I disagree."
    
85.      fi
    
86.      ;;
    
87. "f") exit
    
88.      ;;
    
89. esac
    

复制代码

这是我写的，现在的问题是，在选择完abcd后就直接退出了，没有让用户再做其它选择

还有两个参数在命令行输入，如果输入./lab.bash  2 4 运行时正常

但如果输入./lab.bash  a 3   

请问怎么解决？

afton

jerryjzm

bash +x your_bash_script

来进行调试，看看到底在那个环节不是按照你的思路走的。

afton

bash +x your_bash_script

来进行调试，看看到底在那个环节不是按照你的思路走的。
jerryjzm 发表于 2011-02-20 12:18

   这个调试我还没学，
不过现在就是死循环

afton

现在我已经解决了./lab.bash -14 3 的问题了，

但是我输入./lab.bash a 3 或者./lab.bash 3 3.3就进入死循环

还有Menu的部分，我写了循环语句，为什么执行完option就退出了？

ws039012

不是很清楚，但可以提供个小技巧，如果你不知道死在哪儿，可以在可疑的地方加上一个echo +数字~这样就可以清楚知道程序走到了哪一步~