shell版计算器（支持简单四则运算）
前一段时间受人之托，说是毕业设计非要用shell写个计算器，要支持四则运算的，刚开始觉得还容易，可发现四则的匹配还是比较繁琐的，在这里分享下吧～估计之后也不会出这样的毕业设计了http://blog.51cto.com/neweditor/editor/images/smiley/46.gifPS：赶时间写的，有bug的欢迎指正
[*]#!/bin/bash
[*]
[*]## Calculator.sh ##
[*]main()
[*]{
[*] echo 'This is a Calculator:'
[*] echo 'example: 3 + 90 x ( 9 - 5 ) / 3 - 23'
[*] call
[*]}
[*]
[*]
[*]call()
[*]{
[*] while [ 1 ];do
[*] read str
[*] u=($str)
[*] g1='no'
[*] g2='no'
[*] nu=`echo $str | awk '{print NF}'`
[*] for((i=0;i /dev/null
[*] if (( $? == 0 ));then
[*] echo ${u[$i]} |grep -E '\(|\)' > /dev/null
[*] if (( $? == 0 ));then
[*] echo ${u[$i]} |grep -w '(' > /dev/null
[*] if (( $? == 0 ));then
[*] g1=$i
[*] continue
[*] fi
[*]
[*] echo ${u[$i]} |grep -w ')' > /dev/null
[*] if (( $? == 0 ));then
[*] g2=$i
[*] if [ $g1 != 'no' ] || [ $g2 != 'no' ];then
[*] compute $g1 $g2
[*] u[$g1]=$?
[*] for((p=$g1+1;p /dev/null
[*] if (( $? == 0 ));then
[*] sum=`expr ${s[$k-1]} \* ${s[$k+1]}`
[*] s[$k+1]=$sum
[*] s[$k]=''
[*] s[$k-1]=''
[*] continue
[*] fi
[*]
[*] echo ${s[$k]} |grep -w '/' > /dev/null
[*] if (( $? == 0 ));then
[*] sum=`expr ${s[$k-1]} \/ ${s[$k+1]}`
[*] s[$k+1]=$sum
[*] s[$k]=''
[*] s[$k-1]=''
[*] continue
[*]
[*] fi
[*] fi
[*] echo ${s[@]} |grep -E '+|-' > /dev/null
[*] if (( $? == 0 ));then
[*] t=(${s[@]})
[*] nu2=`echo ${t[@]} | awk '{print NF}'`
[*] for((j=$1;j /dev/null
[*] if (( $? == 0 ));then
[*] echo ${t[$j]} |grep -w '+' > /dev/null
[*] if (( $? == 0 ));then
[*] sum=`expr ${t[$j-1]} + ${t[$j+1]}`
[*] t[$j+1]=$sum
[*] t[$j]=''
[*] t[$j-1]=''
[*] continue
[*] fi
[*]
[*] echo ${t[$j]} |grep -w '-' > /dev/null
[*] if (( $? == 0 ));then
[*] sum=`expr ${t[$j-1]} - ${t[$j+1]}`
[*] t[$j+1]=$sum
[*] t[$j]=''
[*] t[$j-1]=''
[*] continue
[*] fi
[*]
[*] fi
[*] done
[*] fi
[*] done
[*] return $sum
[*]}
运行结果：
[*]zhangbo@ufo:~/me/shell$ ./Calculator.sh
[*]This is a Calculator:
[*]example: 3 + 90 x ( 9 - 5 ) / 3 - 23
[*]3 + 90 x ( 9 - 5 ) / 3 - 23
[*]100
[*]2 x ( 3 + 10 )
[*]26
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