在Linux中shell编程求M-N的阶乘，M、N用户输入

#!/bin/bash

echo "请输入整数M、N(M>N)"

echo "M："

read M

#判断M是否非空且为整数

if [ -z $M ]

then

echo "M 必须非空"

exit 1

elif ! [[ $M =~ ^-?[0-9]*$ ]]

then

echo "M 必须为整数"

exit 1

fi

echo "N："

read N

#判断N是否非空且小于N的整数

if [ -z $N ]

then

echo "N 必须非空"

exit 1

elif ! [[ $N =~ ^-?[0-9]*$ ]]

then

echo "N 必须为整数"

exit 1

elif [ $M -le $N ]

then

echo "N必须小于M"

exit 1

fi

let "base = M-N"

result=1

#阶乘函数，引入result实现运算的线性增长

fac (){

base=$1

result=$2

if [ $base -gt 0 ]

then

let "result *= base"

let "base -= 1"

fac $base $result

fi

}

#计算阶乘

fac $base $result

echo "M-N的阶乘为$result"

exit 0

上次看错题目了

[oracle@localhost test]$ cat c.sh#!/bin/shb=0echo "请出入n的值："read nfor ((a=1a<=na++))dob=1/$a+$bdonec=`bc<<!scale=5$b!`echo "运算式是：$b"echo "最后的结果是：$c"[oracle@localhost test]$ sh c.sh请出入n的值：20运算式是：1/20+1/19+1/18+1/17+1/16+1/15+1/14+1/13+1/12+1/11+1/10+1/9+1/8+1/7+1/6+1/5+1/4+1/3+1/2+1/1+0最后的结果是：3.59768[oracle@localhost test]$

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