shell脚本编译菱形

手动输入菱形的行数 ，打印出菱形

echo "Please input data"
read k //读入手动输出的行数
i=1

while [ $i -le $k ]
do
let ban=k/2+1 //菱形的上半部

  if [ $i -le $ban ] 
  then
       j=1
   while [ $j -le `expr $ban - $i` ]
   do
              printf " "
              let j++
         done
 
         n=1;
     let xing=i*2-1
     while [ $n -le $xing  ]
     do
               printf "*"
                let n++
      done
          printf "\n"

  else   //菱形的下半部分 
         j=1
     while [ $j -le `expr $i - $ban` ]
     do
               printf " "
               let j++
         done
 
          n=1
     let xing1=k-i*2+ban*2
      while [ $n -le $xing1  ]
      do
                printf "*"
                    let n++
      done
      printf "\n"
  fi
  let i++

done