Re^2: New student, can we write this program in perl...

[rahulraina7]

Thank you Choroba Sir for your interest , please have a look at C code.

#include<stdio.h>
#include<conio.h>
void main()
{
int a[20],b[20],c[20],i,j=0,k=0,n;
clrscr();
printf("Enter the number of elements");
scanf("%d",&n);
printf("Enter  n numbers\n");
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
for(i=0;i<n;i++)
{
if((a[i]%2)==0)
{
b[j]=a[i];
j++;
}
else
{
c[k]=a[i];
k++;
}
}
printf("The  even numbers  are\n");
for(i=0;i<j;i++)
{
printf("%d\n",b[i]);
}
printf("The odd numbers are\n");
for(i=0;i<k;i++)
{
printf("%d\n",c[i]);
}
getch();
}

It will basically input an array of 'n' numbers and then separate it into two arrays, one contains odd numbers and one contains even numbers. Hoping to hear from you soon.

[choroba]

I would change your program to this one:

#!/usr/bin/perl
use warnings;
use strict;

print 'Enter the number of elements: ';
my $n = <>;                                     # Read the input.
chomp $n;                                       # Remove the newline.
print "Enter $n numbers.\n";
my @a;
for (1 .. $n) {
    push @a, scalar <>;                         # Push numbers to the 
+array.
}
chomp @a;                                       # Remove the newlines.

print join (' ', 'The even numbers are:',
                 grep $_ % 2, @a),              # grep filters the num
+bers = 1 modulo 2
      "\n";
print join (' ', 'The odd numbers are:',
                 grep 1 - $_ % 2, @a),
      "\n";

Not really similar, is it? The main differences:
• No main function needed.
• Variables are declared where needed.
• The diamond operator is used to read from the input.
• for can be used with simpler syntax, avoiding off by 1 errors (see perlsyn)
• grep can be used to filter arrays. No need for temporary variables to keep the results if you do not need them later.

[Jenda]

use strict;
# #include<conio.h>
#void main()
#{
my (@a,@b,@c,$i,$j,$k,$n);

print("Enter the number of elements\n");
$n = <>;
printf("Enter  %d numbers\n",$n);
for($i=0;$i<$n;$i++)
{
  push @a, scalar(<>);
}
for($i=0;$i<$n;$i++)
{
  if(($a[$i]%2)==0)
  {
    $b[$j]=$a[$i];
    $j++;
  }
  else
  {
    $c[$k]=$a[$i];
    $k++;
  }
}
print("The  even numbers  are\n");
for($i=0;$i<$j;$i++)
{
printf("%d\n",$b[$i]);
}
printf("The odd numbers are\n");
for($i=0;$i<$k;$i++)
{
 printf("%d\n",$c[$i]);
}
<>;
#}

Not that this was the best (or even just a particularly good) way to write this, but it's the minimal change. Huge difference from the C code, right?