shell語法練習(xí)之實(shí)現(xiàn)簡單計(jì)算器

#!/bin/bash
#通過輸入數(shù)據(jù) 計(jì)算相應(yīng)的運(yùn)算結(jié)果
expression='';
calculator(){
    echo "請(qǐng)輸入一個(gè)數(shù):";
    read x;
    echo "請(qǐng)輸入另一個(gè)數(shù):";
    read y;
    echo "請(qǐng)輸入運(yùn)算符號(hào):";
    read symbol;
   case $symbol in 
           +) 
             ret=`expr $x + $y`;
             expression="$x+$y";
             ;;              
          -)
             ret=`expr $x - $y`;
             expression="$x-$y";
            ;;
          \*)
            ret=`expr $x \* $y`;
            expression="$x*$y";
            ;;
         /)
          ret=`expr $x / $y`;
          expression="$x/$y";
          ;;
        %)
            ret=`expr $x % $y`;
             ;;
esac;
return $ret;
}
while :
   do 
     echo "開始計(jì)算:Y/N:";
     read -n1 flg;
     case $flg in 
        n|N)
             echo '計(jì)算已終止';
             break;
                ;; 
      y|Y)
          ;;
    *)
       echo '計(jì)算已終止';
       break;
       ;;
esac; 
    # if [[ $flg ==  "N" ]]
    # then
    #     echo '計(jì)算已終止';
    #     break;
    # fi;
     calculator;
    res=$?
    echo -e "運(yùn)算結(jié)果是:${expression}=$res\n";
done

記錄用shell實(shí)現(xiàn)一個(gè)簡單計(jì)算器效果，運(yùn)行效果截圖：