Shell脚本编程中常用的数学运算实例

2019-09-23 09:38:24丽君

#!/bin/bash
echo "Enter The Number"
read n
num=$(expr $n % 2)
if [ $num -eq 0 ]
then
echo "is a Even Number"
else
echo "is a Odd Number"
fi
输出结果:

[root@tecmint ~]# vi EvenOdd.sh
[root@tecmint ~]# chmod 755 EvenOdd.sh
[root@tecmint ~]# ./EvenOdd.sh
 
Enter The Number
12
is a Even Number
1
2
3
4
5
[root@tecmint ~]# ./EvenOdd.sh
 
Enter The Number
11
is a Odd Number

Factorial数


#!/bin/bash
echo "Enter The Number"
read a
fact=1
while [ $a -ne 0 ]
do
fact=$(expr $fact * $a)
a=$(expr $a - 1)
done
echo $fact
输出结果:
[root@tecmint ~]# vi Factorial.sh
[root@tecmint ~]# chmod 755 Factorial.sh
[root@tecmint ~]# ./Factorial.sh
 
Enter The Number
12
479001600
你可以从这里下载这个例子的代码

判断Armstrong数

Armstrong数:在三位的正整数中,例如abc,有一些可能满足(a^3)+(b^3)+(c^3)=abc,即各个位数的立方和正好是该数的本身。这些数即称为Armstrong数。

#!/bin/bash
echo "Enter A Number"
read n
arm=0
temp=$n
while [ $n -ne 0 ]
do
r=$(expr $n % 10)
arm=$(expr $arm + $r * $r * $r)
n=$(expr $n / 10)
done
echo $arm
if [ $arm -eq $temp ]
then
echo "Armstrong"
else
echo "Not Armstrong"
fi
输出结果:

[root@tecmint ~]# vi Armstrong.sh
[root@tecmint ~]# chmod 755 Armstrong.sh
[root@tecmint ~]# ./Armstrong.sh
 
Enter A Number
371
371
Armstrong
1
2
3
4
5
6
[root@tecmint ~]# ./Armstrong.sh
 
Enter A Number
123
36
Not Armstrong

判断质数


#!/bin/bash
echo “Enter Any Number”
read n
i=1
c=1
while [ $i -le $n ]
do
i=$(expr $i + 1)
r=$(expr $n % $i)
if [ $r -eq 0 ]
then
c=$(expr $c + 1)
fi
done
if [ $c -eq 2 ]
then
echo “Prime”
else
echo “Not Prime”
fi
输出结果:

[root@tecmint ~]# vi Prime.sh
[root@tecmint ~]# chmod 755 Prime.sh
[root@tecmint ~]# ./Prime.sh
 
“Enter Any Number”
12
 
“Not Prime”