请教bc怎么用
听说在控制台下有个计算器 bc可是不太清楚怎么用，不知道哪儿有比较具体的讲解
$ bc
3+5
8
3.0/2.0
1
不知道为什么3.0/2.0等于1， 而不是双精度？ 以前用过，不过今天刚网络重装了系统，居然发现bc命令没有了：（ 设置精度
加入:
scale=4
bc还可以简单的编程,自己还有诸如对数,平方之类的内建函数,其语法类似于C语言.具体的好象在info里面有.比如比较300的阶乘和100的300次方就可以通过bc的编程来完成.而在脚本里面,可以通过here文档的方式来使用bc命令.这个东西很强大的. 设置精度
加入:
scale=4
bc还可以简单的编程,自己还有诸如对数,平方之类的内建函数,其语法类似于C语言.具体的好象在info里面有.比如比较300的阶乘和100的300次方就可以通过bc的编程来完成.而在脚本里面,可以通过here文档的方式来使用bc命令.这个东西很强大的.
应该不错! 设置精度
加入:
scale=4
bc还可以简单的编程,自己还有诸如对数,平方之类的内建函数,其语法类似于C语言.具体的好象在info里面有.比如比较300的阶乘和100的300次方就可以通过bc的编程来完成.而在脚本里面,可以通过here文档的方式来使用bc命令.这个东西很强大的.
多谢！bc是可以编程的，a language，呵呵。有时候在字符模式下可以用来当计算器用。
NUMBERS
The most basic element in bc is the number.Numbers are arbitrary precision numbers.This precisionisbothin
the integer part and the fractional part.All numbers are represented internally in decimal and all computation is
done in decimal.(This version truncates results from divide and multiply operations.)There aretwoattributes
of numbers, the length and the scale.The length is the total number of significant decimal digits in a number and
the scale is the total number of decimal digits after the decimal point.For example:
.000001 has a length of 6 and scale of 6.
1935.000 has a length of 7 and a scale of 3.
VARIABLES
Numbers are stored in two types of variables, simple variables and arrays.Both simple variables andarrayvari-
ables are named.Names begin with a letter followed by any number of letters, digits and underscores.All letters
must be lower case.(Full alpha-numeric names are an extension. In POSIX bc all names are a single lower case let-
ter.) Thetype of variable is clear by the context because all array variable names will be followed by brackets
([]).
There are four special variables, scale, ibase, obase, and last.scale defineshowsomeoperationsusedigits
after the decimal point.The default value of scale is 0. ibase and obase define the conversion base for input and
output numbers.The default for both input and output is base 10.last (an extension) is a variable that hasthe
value of the last printed number.These will be discussed in further detail where appropriate.All of these vari-
ables may have values assigned to them as well as used in expressions. 不错：）
页:
[1]