Linux shell腳本 整型和浮點型運算基礎範例
Linux學習小結 2
1、整型運算
參考代碼如下(示例):包括加減乘除和取餘計算。
#!/bin/bash
a=$1
b=$2
if [ $# -lt 2 ]
then
echo "錯誤!"
echo "請輸入2個數字! 例如: sh test_int_calc.sh 1 2"
#exit
else
a=$1; b=$2
printf "2 個整型資料計算:\r\n"
echo "第一個數為:$1"
echo "第二個數為:$2"
echo "a+b = `expr $a + $b`"
echo "a-b = `expr $a - $b`"
echo "axb = `expr $a \* $b`"
echo "a➗b = `expr $a / $b`"
echo "a%b = `expr $a % $b`"
fi
運作結果:
1、參數錯誤
錯誤!
請輸入2個數字! 例如: sh test_int_calc.sh 1 2
2、參數正确
2 個整型資料計算:
第一個數為:1
第二個數為:2
a+b = 3
a-b = -1
axb = 2
a➗b = 0
a%b = 1
2、浮點型運算
參考代碼如下:
# 浮點數的示例
# bash中“bc”工具的基本用法
a=3.33
b=3.3
c=$(echo "$a + $b" | bc)
d=$(echo "$a * $b" | bc)
e=$(echo "scale=5; $a / $b" | bc)
echo "c=a+b=$a+$b=$c"
echo "d=a*b=$a*$b=$d"
echo "e=a/b=$a/$b=$e"
# bc的-l參數表示使用數學庫
pi=$(echo "scale=10; 4*a(1)" | bc -l)
s=$(echo "s($pi/6)" | bc -l)
echo "pi=$pi"
echo "s=sin(pi/6)=$s"
# 使用BC工具的更多選項
r=$(echo 'ibase=10;obase=2; 15+16' | bc)
echo "binary of (15+16) is $r"
# 使用bc比較浮點數
big=100
small=99.9
if [ $(echo "$big > $small" | bc) -eq 1 ]; then
echo "$big is bigger than $small"
fi
# 用awk 處理浮點數
echo $(awk -v x=10 -v y=2.5 'BEGIN {printf "10/2.5=%.2f\n",x/y}')
v=$(echo $big $small | awk '{ printf "%0.8f\n" ,$1/$2}')
echo "$big / $small = $v"
echo $big $small | awk '{if($1>$2) {printf"%f > %f\n",$1,$2} else {printf"%f <%f\n",$1,$2}}'
運作結果:
c=a+b=3.33+3.3=6.63
d=ab=3.333.3=10.98
e=a/b=3.33/3.3=1.00909
pi=3.1415926532
s=sin(pi/6)=.49999999994373819220
binary of (15+16) is 11111
100 is bigger than 99.9
10/2.5=4.00
100 / 99.9 = 1.00100100
100.000000 > 99.900000