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Here's the code; it's in Perl.
use warnings;
use strict;
use Data::Dumper;
print "I'll show the prime numbers between 2 and u numbers for you.\n";
print "Pls, enter u numbers.";
my $numberer = <STDIN>;
my #nonprime = qw();
my #all = qw();
for (my $i = 3; $i < $numberer; $i++) {
my $lenght = #all;
$all[$lenght] = $i;
for (my $i = 3; $i < $numberer; $i++) {
if ($numberer <= 3) {
print "It's none.";
} else {
for (my $i = 3; $i < $numberer; $i++) {
for (my $j = 2; $j < $numberer; $j++) {
if ($i == $j) {
} elsif ($i % $j == 0) {
my $len = #nonprime;
$nonprime[$len] = $i;
} else {
}
}
}
}
my %h;
#h{#nonprime} = #nonprime;
print Dumper [grep {!exists $h{$_}} #all];
Can you help me by explaining what the problem is? I try to learn perl programming and do some exercise that is "Write your own program to capture all the prime numbers between 2 and a number the user
gives you."
Might be this code will help you for your question.
#!/usr/bin/perl
use warnings;
use strict;
sub testprime
{
my $m = shift #_;
my $i = 2;
while ($i < $m)
{
return 0 unless ($m % $i++);
}
return 1;
}
print "Enter a number to find the prime \n";
chomp (my $n = <STDIN>);
system 'cls';
for(my $i=2; $i<=$n; $i++)
{
my $FindPrime = testprime $i;
if ( $FindPrime == 1)
{
print "Yes, the given number - $i is Prime \n";
}
else
{
print "No, It is NOT a prime Number - $i \n";
}
}
Thnx.
Related
This is supposed to put the contents of nums into decreasing order, however sort does not change the contents of nums. Many sites I read have said to pass by reference, but I don't think I'm dereferencing the argument correctly. Bear with me, this is my first Perl program :)
#! /usr/bin/env perl
sub sort {
my #arr = #_;
my $len = scalar #arr;
for (my $i = 1; $i < $len-1; $i = $i + 1) {
my $max = $i;
for (my $j = $i + 1; $j < $len; $j = $j + 1) {
if ($arr[$j] > $arr[$max]) {
$max = $j
}
}
$temp = $arr[$max];
$arr[$max] = $arr[$i];
$arr[$i] = $temp;
}
}
print "Enter 10 numbers: ";
my $numbers = <STDIN>;
my #nums = split ' ', $numbers;
print "Unsorted: #nums\n";
sort \#nums;
print "Sorted: #nums\n";
#Matt Jacob helped me out with this one. This is what I was looking for.
#! /usr/bin/env perl
sub selection_sort {
my $arr = shift;
my $len = scalar #$arr;
for (my $i = 0; $i < $len-1; $i++) {
my $max = $i;
for (my $j = $i + 1; $j < $len; $j++) {
if (#$arr[$j] > #$arr[$max]) {
$max = $j
}
}
my $temp = #$arr[$max];
#$arr[$max] = #$arr[$i];
#$arr[$i] = $temp;
}
}
print "Enter 10 numbers: ";
my $input = <STDIN>;
my #integers = split ' ', $input;
print "Unsorted: #integers\n";
selection_sort \#integers;
print "Sorted: #integers\n";
I'm trying to write a program that can read from a file then put into a heap sort then output in a tree along with the sorted list. But I got stuck, instead of having the put be the numbers used in the heap sort, it just post 1-10 on one line then 1-9 on the next line. I'm really confused and I barely understand this language as it is. I put a example of the out below alone with the output I am hoping to have it draw.
#!/usr/bin/perl
use 5.006;
use strict;
use warnings;
use Tree::DAG_Node;
process_data(read_file('testing.txt'));
process_data((3,1,4,1,5,9,2,6,5,3,6));
sub read_file{
my($filename)=#_;
my #data=();
my #words;
open(my $fh, "<", $filename)
or die "Could not open file: $!\n";
while(<$fh>){
chomp;
#words = split(' ');
foreach my $word(#words){
push #data, $word;
}
}
close $fh;
return #data;
}
sub heap_sort {
my ($a) = #_;
my $n = #$a;
for (my $i = ($n - 2) / 2; $i >= 0; $i--) {
down_heap($a, $n, $i);
}
for (my $i = 0; $i < $n; $i++) {
my $t = $a->[$n - $i - 1];
$a->[$n - $i - 1] = $a->[0];
$a->[0] = $t;
down_heap($a, $n - $i - 1, 0);
}
}
sub down_heap {
my ($a, $n, $i) = #_;
while (1) {
my $j = max($a, $n, $i, 2 * $i + 1, 2 * $i + 2);
last if $j == $i;
my $t = $a->[$i];
$a->[$i] = $a->[$j];
$a->[$j] = $t;
$i = $j;
}
sub max {
my ($a, $n, $i, $j, $k) = #_;
my $m = $i;
$m = $j if $j < $n && $a->[$j] > $a->[$m];
$m = $k if $k < $n && $a->[$k] > $a->[$m];
return $m;
}
}
sub draw_tree{
my(#data)=#_;
my $root = Tree::DAG_Node->new;
$root->name($_[0]);
$root->new_daughter->name($_) for (1..10);
my #names = #data;
my $count = 50;
for my $n ($root->daughters) {
for (split //, $names[$count++]) {
$n->new_daughter->name($_)
}
}
print map "$_\n", #{$root->draw_ascii_tree};
}
sub process_data{
my(#data)=#_;
my #a = #data;
print "#a\n";
print "\n";
heap_sort(\#a);
draw_tree(#a);
print "\n";
print "#a\n";
print "\n";
}
here is the output I get
CMD output of my code
Output I am expecting:
(using example data)
1 1 9 4 5
1
|
1 ----- 9
|
/\
4 5
1 1 4 5 9
When ever I run this bit of code. it doesn't display any output. Anyone see anything wrong?
I am trying to display this in the out put:
A
AA
AAA
AAAB
AAABA
AAABAA
AAABAAA
AAABAAAB
etc.
#!/usr/local/bin/perl
$A = 3;
$B = 1;
$i = 1;
$output = "";
$j = 1;
while ($i <= $ARGV[0]) {
while ($j <= $i) {
if ($A == 0 && $B == 0) {
$A = 3;
$B = 1;
}
if ($A > 0) {
$output.= "A";
$A--;
}
else {
$output.= "B";
$B--;
}
$j++;
}
print($output . "\n");
$i++;
}
It works for me when I run it with a numeric argument (number of lines).
An idea how to simplify the code:
#!/usr/bin/perl
use warnings;
use strict;
my $count = shift;
my $A = 3;
my $B = 1;
my $string = q();
$string .= ('A' x $A) . ('B' x $B) while $count > length $string;
print substr($string, 0, $_), "\n" for 1 .. $count;
It uses a different algorithm - it creates the longest possible string, and then outputs parts of it.
if there is no #ARGV, while ($i <= $ARGV[0]) never runs.
#ARGV is an array of the command line arguments provided when the script is executed. you did not provide any command line arguments. if you had use warnings in effect, you would be warned that $ARGV[0] is uninitialized.
As from ikegami comment. You cann't pass the input at when the program is compile. For example, consider your file name is algo.pl. Can you run your program with
perl algo.pl 10
Here 10 is the input value of the program. In program value is retrieve by the $ARGV[0]
so in your program looks like while ($i <= $ARGV[0]).
If you want pass the several values like perl filename.pl 12 data1 data2In your data retrieve by $ARGV[0] $ARGV[1] $ARGV[2] for more information see here.
If you want pass the input at the time of execution used STDIN
use warnings;
use strict;
my $A = 3;
my $B = 1;
my $i = 1;
my $output = "";
my $j = 1;
print "Enter the value: ";
chomp(my $value = <STDIN>);
while ($i <= $value) {
while ($j <= $i) {
if ($A == 0 && $B == 0) {
$A = 3;
$B = 1;
}
if ($A > 0) {
$output.= "A";
$A--;
}
else {
$output.= "B";
$B--;
}
$j++;
}
print($output . "\n");
$i++;
}
I am trying to perform a transpose on a data contained in a file. The data is as follows:
1 2 3 4 5
2 3 4 5 6
4 5 6 7 9
4 3 7 6 9
I am getting the result as follows which is incorrect. I am not getting the error in the code due to which the last column is not transposed properly. Any solution...
Code:
#!/usr/bin/perl
use strict;
use warnings;
my #dependent; # matrix of dependent variable
# Reading the data from text file to the matrix
open( DATA, "<example.txt" ) or die "Couldn't open file , $!"; #depenedent
# Storing data into the array in matrix form
while ( my $linedata = <DATA> ) {
push #dependent, [ split '\t', $linedata ];
}
my $m = #dependent;
#print "$m\n";
my $n = #{ $dependent[1] };
#print $n;
#print "Matrix of dependent variables Y \n";
for ( my $i = 0; $i < $m; $i++ ) {
for ( my $j = 0; $j < $n; $j++ ) {
#print $dependent[$i][$j]," ";
}
#print "\n";
}
my #transpose;
for ( my $i = 0; $i < $n; $i++ ) {
for ( my $j = 0; $j < $m; $j++ ) {
$transpose[$i][$j] = $dependent[$j][$i];
}
}
for ( my $i = 0; $i < $n; $i++ ) {
for ( my $j = 0; $j < $m; $j++ ) {
print $transpose[$i][$j], " ";
}
print "\n";
}
chomp your data when you read it, before you split it; your strange output is caused by the last element of each row of the input still having a newline attached.
Just as a side note, DATA isn't a very good name to pick for a filehandle; perl already defines a special builtin filehandle named DATA for reading data that's embedded in a script or a module, so using that name for yourself can lead to confusion :)
I'm fairly new to coding in Perl and am used to using C-style for loops. I'm not sure why the following program never prints a value of 4 for $l:
use strict;
use warnings;
my $minL = 4;
for (my $l = $minL; $l > 0; $l--) {
for (my $i = 0; $i + $l < $minL; $i++) {
print "$i $l\n";
}
}
Many thanks in advance.
Your inner for loop has the condition $i + $l < $minL. If $l == $minL, then $i + $l < $minL will be false even if $i is 0, so the loop runs 0 times and never prints anything.
Maybe you wanted to use <= for the condition?
By the way, here is how you could write the same thing (assuming the <= condition) using Perl-style foreach loops:
my $minL = 4;
for my $l (reverse 1 .. $minL) {
for my $i (0 .. $minL - $l) {
print "$i $l\n";
}
}
In the first iteration:
for (my $l = $minL; $l > 0; $l--) {
$l == $minL
for (my $i = 0; $i + $l < $minL; $i++) {
So this block won't run until $l is decremented:
print "$i $l\n";
}
Change your inner loop to:
for (my $i = 0; $i + $l <= $minL; $i++) {