in reply to Constructing complex numbers using recursion

You may find this an interesting starting point: 

use strict;
use warnings;
my $x = "3 _ 4"; #in polar form.. 3 is mag and 4 is angle
my $y = "1i2"; #in rectangular form

print join ", ", constructComplex ($x);
print "\n" . join ", ", constructComplex ($y);

sub constructComplex
{
my $value1 = shift;
my @construct;
my ($a, $Form, $b) = $value1 =~ /([-+e.\d]+)\s*([i_])\s*([-+e.\d]+)/;

return undef if ! defined $b;

$value1 = $_[0];
if ($Form eq '_')
  {
  #uses $value1 to pick out the magnitude and angle
  my ($magnitude, $angle) = ($a, $b);
  $construct[2] = $magnitude;
  $construct[3] = $angle;
  # Do da polar to rect conversion
  }
else
  {
  my ($real, $complex) = ($a, $b);
  $construct[0] = $real;
  $construct[1] = $complex;
  # Do da rect to polar conversion
  }
 
return @construct; 
}

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Ignoring undef related warnings it prints:

, , 3, 4
1, 2

[download]
Perl is Huffman encoded by design.

Replies are listed 'Best First'.
Re^2: Constructing complex numbers using recursion
by moltar512 (Sexton) on Nov 08, 2005 at 05:03 UTC
    ya.. i'm way to green to read regular expressions :( :(
    here is my constructComplex method in it's entirety, for extreme clarity 
    sub constructComplex {
    my $value1 = $_[0];
    my $value2 = $_[1];
    
    my ($real1, $real2, $complex1, $complex2, $magnitude1, $magnitude2
+, $angle1, $angle2, @constructed,  @constructedvalue1Polar, @construc
+tedvalue1Rect, @constructedvalue2Polar, @constructedvalue2Rect, $valu
+e1isRectangular, $value2isRectangular);

    #if value1 is in rectangular form
    if(rindex($value1, "_") < 0)
    {
        $value1isRectangular = 1;
    }

    #if value1 is in polar form
    if(rindex($value1, "_") > 0)
    {
        $value1isRectangular = 0;

        $magnitude1 = substr($value1, 0, index($value1, " "));
        $angle1 =substr($value1, (rindex($value1, " ") + 1), length($v
+alue1));
        
        #@constructedvalue1Polar = &constructComplex(&PolarToRect($val
+ue1));
        #$real1 = $constructedvalue1Polar[0];
        #$complex1 = $constructedvalue1Polar[2];
    }

    #if value2 is in rectangular form
    if(rindex($value2, "_") < 0)
    {
        $value2isRectangular = 1;
    }

    #if value2 is in polar form
    if(rindex($value2, "_") > 0)
    {
        $value2isRectangular = 0;

        $magnitude2 = substr($value2, 0, index($value2, " "));
        $angle2 =substr($value2, (rindex($value2, " ") + 1), length($v
+alue2));
    }

##############
    if($value1isRectangular)
    {

        #lowercases everything
        $value1 = lc($value1);

        #if a j is found, turns it into an i
        if(rindex($value1, "j") > 0)
        {
            substr ($value1, rindex($value1, "j"), 1, "i");
        }

        #if there is no space, and there is no i, then there must ONLY
+ be a real part
        if(index($value1, " ") < 0 && index($value1, "i") < 0)
        {
            $real1 = substr($value1, 0, length($value1));
        }
        #if there is no space, but there is an i, then there is no rea
+l part, real is 0
        elsif(index($value1, " ") < 0 && index($value1, "i") > 0)
        {
            $real1 = "0";
        }
        #else, there is a space, meaning both real and complex
        else
        {
            $real1 = substr($value1, 0, index($value1, " "));
        }

        #"7 + i"
        if((index($value1, " ") > 0) && (index($value1, "i") > 0) && (
+(rindex($value1, " ") + 1) == index($value1, "i")))
        {
            $complex1 = "1";
        }
        #"7 + -i" and "-i"
        #elsif((index($value1, " ") > 0) && (index($value1, "i") > 0) 
+&& (index($value1, "-") > 0) && ((rindex($value1, " ") + 1) == rindex
+($value1, "-")) && ((rindex($value1, "-") + 1) == rindex($value1, "i"
+)))
        elsif(index($value1, "-i") != -1)
        {
            $complex1 = "-1";
        }
        #"i"
        elsif((index($value1, "i") == 0))
        {
            $complex1 = "1";
        }
        #"-Bi"
        elsif((index($value1, " ") < 0) && (index($value1, "i") > 0) &
+& (index($value1, "-") != -1) && (index($value1, "i") != 0) && ((inde
+x($value1, "-") +1) != index($value1, "i")))
        {
            $complex1 = substr($value1, 0, index($value1, "i"));
        }
        #"Bi"
        elsif((index($value1, " ") < 0) && (index($value1, "i") > 0) &
+& (index($value1, "-") < 0) && (index($value1, "i") != 0))
        {
            $complex1 = substr($value1, 0, index($value1, "i"));
        }
        #"30"
        elsif(index($value1, "i") < 0)
        {
            $complex1 = 0
        }
        else
        {
            $complex1 = substr($value1, (rindex($value1, " ") + 1), in
+dex($value1, "i"));
        }

        #if negative by sign, changes element to negative
        if(index($value1, " - ") > 0)
        {
            $complex1 = -$complex1;
        }
    }

    if($value2isRectangular)
    {
        #lowercases everything
        $value2 = lc($value2);

        #if a j is found, turns it into an i
        if(rindex($value2, "j") > 0)
        {
            substr ($value2, rindex($value2, "j"), 1, "i");
        }

        #if there is no space, and there is no i, then there must ONLY
+ be a real part
        if(index($value2, " ") < 0 && index($value2, "i") < 0)
        {
            $real2 = substr($value2, 0, length($value2));
        }
        #if there is no space, but there is an i, then there is no rea
+l part, real is 0
        elsif(index($value2, " ") < 0 && index($value2, "i") > 0)
        {
            $real2 = "0";
        }
        #else, there is a space, meaning both real and complex
        else
        {
            $real2 = substr($value2, 0, index($value2, " "));
        }

        #"7 + i"
        if((index($value2, " ") > 0) && (index($value2, "i") > 0) && (
+(rindex($value2, " ") + 1) == index($value2, "i")))
        {
            $complex2 = "1";
        }
        #"7 + -i" and "-i"
        #elsif((index($value2, " ") > 0) && (index($value2, "i") > 0) 
+&& (index($value2, "-") > 0) && ((rindex($value2, " ") + 1) == rindex
+($value2, "-")) && ((rindex($value2, "-") + 1) == rindex($value2, "i"
+)))
        elsif(index($value2, "-i") != -1)
        {
            $complex2 = "-1";
        }
        #"i"
        elsif((index($value2, "i") == 0))
        {
            $complex2 = "1";
        }
        #"-Bi"
        elsif((index($value2, " ") < 0) && (index($value2, "i") > 0) &
+& (index($value2, "-") != -1) && (index($value2, "i") != 0) && ((inde
+x($value2, "-") +1) != index($value2, "i")))
        {
            $complex2 = substr($value2, 0, index($value2, "i"));
        }
        #"Bi"
        elsif((index($value2, " ") < 0) && (index($value2, "i") > 0) &
+& (index($value2, "-") < 0) && (index($value2, "i") != 0))
        {
            $complex2 = substr($value2, 0, index($value2, "i"));
        }
        #"30"
        elsif(index($value2, "i") < 0)
        {
            $complex2 = 0
        }
        else
        {
            $complex2 = substr($value2, (rindex($value2, " ") + 1), in
+dex($value2, "i"));
        }

        #if negative by sign, changes element to negative
        if(index($value2, " - ") > 0)
        {
            $complex2 = -$complex2;
        }
    }


#if($real1 ||= 0) {$real1 = 0};
#if($real2 ||= 0) {$real2 = 0};
#if($complex1 ||= 0) {$complex1 = 0};
#if($complex2 ||= 0) {$complex2 = 0};

    $constructed[0] = $real1;
    $constructed[1] = $real2;
    $constructed[2] = $complex1;
    $constructed[3] = $complex2;
    $constructed[4] = $magnitude1;
    $constructed[5] = $magnitude2;
    $constructed[6] = $angle1;
    $constructed[7] = $angle2;

#return "R1: " . $real1 . " C1: " . $complex1 . " R2: " . $real2 . " C
+2: " . $complex2 . " M1: " . $magnitude1 . " A1: " . $angle1 . " M2: 
+" . $magnitude2 . " A2: " . $angle2;

return @constructed;

}

sub PolarToRect {
my ($value1, $real1, $complex1, $magnitude1, $angle1, $complex, @const
+ruct);

$value1 = $_[0];

@construct = &constructComplex($value1);

$magnitude1 = $construct[4];
$angle1 = $construct[6];

#return "M: " . $magnitude1 . " A: " . $angle1;

$real1 = $magnitude1*cos($angle1*($pi/180));
$complex1 = $magnitude1*sin($angle1*($pi/180));

#return "R: " . $real1 . " C: " . $complex1;

if($complex1 < 0)
{
$complex = $real1 . " - " . -$complex1 . "i";
}
else
{
$complex = $real1 . " + " . $complex1 . "i";
}
}

my $z = "5 _ 36.87";
my $y = "6 _ 45.67";

print PolarToRect($z) . "\n";

    [download]
[reply]
[d/l]

      That is not extreme clarity, that is extreme obfusication! Too much code to illustrate a simple problem.

      A lot of the power in Perl involves regexen, learn to use them! Have a look at perlretut and perlre. Search for regex - it's a topic that comes up often. Play with regexen and ask questions about them. If you are using Perl you are using regexen or you are not doing it Right™.

      Go back to my sample and pick it appart until you understand it, or ask specific questions - after reading the documentation linked above.

      Perl is Huffman encoded by design.
[reply]
      Grandfather is right -- this is the extreme opposite of clarity.

      You definitely want to start over, and Grandfather's code is a good place to start. Programming hint: if you had structured your original "constructComplex" sub so that it keeps its two input args in an array and loops over each array element, you would have had about one half as many lines of code. That's true no matter what language you think in. And once you get used to thinking in Perl (and learn something about regexes), you'll be able to shorten -- and clarify -- the code quite a lot more.

[reply]

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