在Unix中提示用户输入两个数字以进行计算 [英] Prompting a user for two numbers in Unix to make a calculation

问题描述

我想编写一个脚本，该脚本将提示用户输入两个数字，以厘米为单位表示矩形的宽度和高度，并以平方厘米和平方英寸的形式输出矩形的面积。在Unix中（一英寸= 2.54厘米）。

I want to write a script which will prompt the user for two numbers, representing the width and height of a rectangle in centimetres and output the area of the rectangle in both square centimetres and square inches. In Unix ( one inch = 2.54 centimetres).

我认为它类似于：

echo "Please enter the width:"
read width

echo "Please enter the second height"
read height

ANS=`expr width \* height`
echo "$ANS"

任何帮助将不胜感激

推荐答案

短一个：）

#!/bin/bash
read -p "Width  in cm (default 1)? " w
read -p "Height in cm (default 1)? " h
read acm ain <<<$(dc<<<"5k${w:-1}sa${h:-1}sb2.54silalb*sclcli/li/sdlcps.ldps.q")
echo "width: ${w:-1}(cm), height: ${h:-1}(cm) - Area: $acm (sqcm) $ain (sqin)"

编辑：添加了说明

dc 是 RPN 计算器，然后执行下一个

the dc is RPN calculator, and doing the next

• 将精度设置为5


• 数字$ w（如果不是se t 1）存储到 a


• 将$ h存储到 b


• 2.54存储到i


• 取 a取 b，并将结果存储乘以 c


• 取 c取 i并除，再次取 i除，再存储结果为 d


• 取 c并打印


• 取 d并打印


• 退出

• set precision to 5
• number $w (if not set 1) store to "a"
• number $h store to "b"
• 2.54 store to i
• take "a" take "b" and multiply result store to "c"
• take "c" take "i" and divide, again take "i" divide again, store the result to "d"
• take "c" and print
• take "d" and print
• quit

在正常数学中：

a=$w; b=$h; i=2.54; c=a*b; d=c/i/i ; print c; print d

和脚本，

• << 是单行 heredoc- dc 将从标准输入中读取它作为输入


• $（commnad）意思是：用命令的结果替换$（命令）


• read xy<< 表示将两个值读入变量x和y（ dc 返回2个值）

• <<< is the one-line "heredoc" - dc will read it as its input from stdin
• $(commnad) mean: replace the $(command) with the result of the command
• read x y <<< mean read two values into the variable x and y (the dc returns 2 values)

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