Well, the shell does not support anything except integer arithmetic. In your case, all the numbers are getting rounded down, so your answer is 42. Try using bc for this:
I have installed Windows and Linux on the same machine but now it starts with windows all the time i need to get in and install Lilo but i don't know how i can get access to my Linux system, i have created an boot disk but it tries to start the installation all the time, i need to boot so i can get... (3 Replies)
Hi,
I have a variable (x) that holds a file name - I need to write this:
if x matches the patern *ABC* or the pattern DEF*T then
action A
else
action B
fi
how to do that?
Also, how can i change the or test to AND test?
Thanks. (2 Replies)
Hi, new to the forums and just need a little help, I have a sript to write and as far as I can see it should work fine but it refuses to run properly, it has issues with the end of a line but I see no issue, would anyone assist please, I just someone to seconed check I have not overlooked something... (5 Replies)
Hello. I'm a complete newbie to C programming. I have a C program that wasn't written by me where I need to write some wrappers around it to automate and make it easier for a client to use. The problem is that the program accepts standard input to control the program... I'm hoping to find a simple... (6 Replies)
hey all, im new and my first question is:
say i have a word "blahblah"
how do i get and replace the last letter of the word with say k, so replace the h with a k.
However you cant just replace the h it has to change the LAST LETTER of the word.
Cheers In advance.
:b: (0 Replies)
Hello all!
This is my first post and I'm very new to programming. I would like help creating a simple perl or bash script that I will be using in my work as a junior bioinformatician.
Essentially, I would like to take a tab-delimted or .csv text with 3 columns and write them to a "3D" matrix:
... (16 Replies)
Cheers!
In /etc/syslog.conf, if an error type is not specified, is it logged anywhere (most preferable is it logged to /var/log/messages) or not?
To be more precise I am interested in error and critical level messages. At default these errors are not specified in syslog.conf, and I need to... (6 Replies)
The attachment says it all really...
It is a DEMO at a glance digital readout using the "date" command to make it useful...
For a Mocbook Pro 13", OSX 10.7.5, but may well work on Linux variants too.
Enjoy...
#!/bin/bash
#
# Clock.sh
# A bash DEMO to create a 6 x 7 character set... (4 Replies)
Discussion started by: wisecracker
4 Replies
LEARN ABOUT SUSE
integer
integer(3pm) Perl Programmers Reference Guide integer(3pm)NAME
integer - Perl pragma to use integer arithmetic instead of floating point
SYNOPSIS
use integer;
$x = 10/3;
# $x is now 3, not 3.33333333333333333
DESCRIPTION
This tells the compiler to use integer operations from here to the end of the enclosing BLOCK. On many machines, this doesn't matter a
great deal for most computations, but on those without floating point hardware, it can make a big difference in performance.
Note that this only affects how most of the arithmetic and relational operators handle their operands and results, and not how all numbers
everywhere are treated. Specifically, "use integer;" has the effect that before computing the results of the arithmetic operators (+, -,
*, /, %, +=, -=, *=, /=, %=, and unary minus), the comparison operators (<, <=, >, >=, ==, !=, <=>), and the bitwise operators (|, &, ^,
<<, >>, |=, &=, ^=, <<=, >>=), the operands have their fractional portions truncated (or floored), and the result will have its fractional
portion truncated as well. In addition, the range of operands and results is restricted to that of familiar two's complement integers,
i.e., -(2**31) .. (2**31-1) on 32-bit architectures, and -(2**63) .. (2**63-1) on 64-bit architectures. For example, this code
use integer;
$x = 5.8;
$y = 2.5;
$z = 2.7;
$a = 2**31 - 1; # Largest positive integer on 32-bit machines
$, = ", ";
print $x, -$x, $x + $y, $x - $y, $x / $y, $x * $y, $y == $z, $a, $a + 1;
will print: 5.8, -5, 7, 3, 2, 10, 1, 2147483647, -2147483648
Note that $x is still printed as having its true non-integer value of 5.8 since it wasn't operated on. And note too the wrap-around from
the largest positive integer to the largest negative one. Also, arguments passed to functions and the values returned by them are not
affected by "use integer;". E.g.,
srand(1.5);
$, = ", ";
print sin(.5), cos(.5), atan2(1,2), sqrt(2), rand(10);
will give the same result with or without "use integer;" The power operator "**" is also not affected, so that 2 ** .5 is always the
square root of 2. Now, it so happens that the pre- and post- increment and decrement operators, ++ and --, are not affected by "use
integer;" either. Some may rightly consider this to be a bug -- but at least it's a long-standing one.
Finally, "use integer;" also has an additional affect on the bitwise operators. Normally, the operands and results are treated as unsigned
integers, but with "use integer;" the operands and results are signed. This means, among other things, that ~0 is -1, and -2 & -5 is -6.
Internally, native integer arithmetic (as provided by your C compiler) is used. This means that Perl's own semantics for arithmetic
operations may not be preserved. One common source of trouble is the modulus of negative numbers, which Perl does one way, but your
hardware may do another.
% perl -le 'print (4 % -3)'
-2
% perl -Minteger -le 'print (4 % -3)'
1
See "Pragmatic Modules" in perlmodlib, "Integer Arithmetic" in perlop
perl v5.12.1 2010-04-26 integer(3pm)