Shell 程式設計--九九乘法表--等邊三角形--菱形

九九乘法表

#!/bin/bash
sum=0
for ((a=1; a<=9; a++))
do
  for ((b=1; b<=$a; b++))
  do
  sum=$[$a*$b]
  echo -ne "$a*$b=$sum\t"
  done
echo ""
done
[root@localhost ~]# chmod +x qqq.sh 
[root@localhost ~]# ./qqq.sh 
1*1=1	
2*1=2	2*2=4	
3*1=3	3*2=6	3*3=9	
4*1=4	4*2=8	4*3=12	4*4=16	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	8*7=56	8*8=64	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45	9*6=54	9*7=63	9*8=72	9*9=81

等邊三角形

[root@localhost ~]# vim aaa.sh
#!/bin/bash
for ((i=1; i<=9; i++))
do
   for ((a=9; a>=$i; a--))
   do
     echo -n " "
   done
   for ((b=1; b<=i; b++))
   do
     echo -n "$i "
   done
   echo ""
done
[root@localhost ~]# chmod +x aaa.sh 
[root@localhost ~]# ./aaa.sh 
         1 
        2 2 
       3 3 3 
      4 4 4 4 
     5 5 5 5 5 
    6 6 6 6 6 6 
   7 7 7 7 7 7 7 
  8 8 8 8 8 8 8 8 
 9 9 9 9 9 9 9 9 9 

菱形

[root@localhost ~]# vim zzz.sh 

#!/bin/bash
for ((i=9; i>=1; i--))
do
  for ((a=1; a<=$i; a++))
  do
  echo -n " "
  done

  for ((b=9; b>=$i; b-- ))
  do
  echo -n "$i"
  done

  for ((c=8; c>=$i; c--))
  do
  echo -n "$i"
  done
  echo ""
done

for ((i=2; i<=9; i++))
do
  for ((a=1; a<=$i; a++))
  do
  echo -n " "
  done
  for ((b=9; b>=$i; b--))
  do
  echo -n "$i"
  done
  for ((c=8; c>=$i; c--))
  do
  echo -n "$i"
  done
  echo ""
done
[root@localhost ~]# chmod +x zzz.sh 
[root@localhost ~]# ./zzz.sh 
         9
        888
       77777
      6666666
     555555555
    44444444444
   3333333333333
  222222222222222
 11111111111111111
  222222222222222
   3333333333333
    44444444444
     555555555
      6666666
       77777
        888
         9