Liunx学习笔记19bc计算器

[root@CentOS4 ~]# bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.



(interrupt) use quit to exit.


(interrupt) use quit to exit.

quit
[root@CentOS4 ~]#

--在bc上常用的运算符有：
+    加法
-    减法
*    乘法
/    除法（在没有设置scale精确度时候，自动取整）
^    指数
%    求余数（取模）

在bc上还可以使用
    ++ 变量             
           -- 变量
           变量 ++   
           变量 --

[root@CentOS4 ~]# bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
1+2
3
234+23/2*3
267
25^3
15625
100%4
0
100%23
8
quit
[root@CentOS4 ~]#


[root@CentOS4 ~]# bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
scale=2 /*scale=number*/
11/4
2.75
11/3
3.66
quit
[root@CentOS4 ~]#
说明：scale=2 是设置小数精确度。/*备注部分*/


bc还可以运行一个带有复杂运算的程序文件（这属于bc的一个扩展属性），如：
The following is code that uses the extended features of bc to  implement  
a  simple program for calculating checkbook balances.  
This program is best kept in a file so that it can be used many times  without
having to retype it at every use.

--使用vi建立一个test运算程序：
root@CentOS4 ~]# vi test

scale=2
print ""nCheck book program!"n"
print " Remember,deposits are negative transaction."n"

print "Initial balance?";bal=read()
bal /= 1
print ""n"
while (1){
        "current balance = ";bal
        "transaction?";trans =read()
        if(trans == 0) break;
        bal -= trans
        bal /= 1
}
~
~
~
"test" [New] 14L, 268C written                                
[root@CentOS4 ~]# ls
--计算结果：

[root@CentOS4 ~]# bc "test
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.

Check book program!
 Remember,deposits are negative transaction.
Initial balance?560

current balance = 560.00
transaction?400
current balance = 160.00
transaction?100
current balance = 60.00
transaction?0
quit
[root@CentOS4 ~]#


今天就学到这些，发现很多内容非常的有意思。

就近来的学习总结出，要想学好Linux，重要一点是英语要学好。
虽然大致的意思能看明白，但很吃力，
经常金山词霸来查某一个单词的意思，这样往往浪费了很多的时间
在解决单词的意思。