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Articles on Trending Technologies
Technical articles with clear explanations and examples
Dereferencing in Perl
Dereferencing in Perl returns the value from a reference point to the location. To dereference a reference simply use $, @ or % as a prefix of the reference variable depending on whether the reference is pointing to a scalar, array, or hash. Following is the example to explain the concept −Example#!/usr/bin/perl $var = 10; # Now $r has reference to $var scalar. $r = \$var; # Print value available at the location stored in $r. print "Value of $var is : ", $$r, ""; @var = (1, 2, 3); # Now $r has reference to @var ...
Read MoreFind the maximum element in an array which is first increasing and then decreasing in C++
Suppose we have one array, which is initially increasing then decreasing. We have to find the max value in the array. So if the array elements are like A = [8, 10, 20, 80, 100, 250, 450, 100, 3, 2, 1], then output will be 500.We can use the binary search to solve this. There are three conditions −When mid is greater than both of its adjacent elements, then mid is maximumIf mid is greater than the next element, but smaller than previous element, then max lies on the left side of mid.If mid element is smaller than the next ...
Read MoreCircular References in Perl
A circular reference in Perl occurs when two references contain a reference to each other. You have to be careful while creating references otherwise a circular reference can lead to memory leaks. Following is an example −Example#!/usr/bin/perl my $foo = 100; $foo = \$foo; print "Value of foo is : ", $$foo, "";OutputWhen the above program is executed, it produces the following result −Value of foo is : REF(0x9aae38)
Read MoreFind the mean vector of a Matrix in C++
Suppose we have a matrix of order M x N, we have to find the mean vector of the given matrix. So if the matrix is like −123456789Then the mean vector is [4, 5, 6] As the mean of each column is (1 + 4 + 7)/3 = 4, (2 + 5 + 8)/3 = 5, and (3 + 6 + 9)/3 = 6From the example, we can easily identify that if we calculate the mean of each column will be the mean vector.Example#include #define M 3 #define N 3 using namespace std; void calculateMeanVector(int mat[M][N]) { cout
Read MoreFind the minimum value to be added so that array becomes balanced in C++
Suppose we have an array A with n elements. And the n is even. We have to find the value that needs to balance the array. As the size of the array is even, then we can make two halves. Sum of the left half and sum of the right half needs to be balanced. So if the array is like A = [1, 2, 3, 2, 5, 3] The sum of left half is 6, and sum of right half is 10. so we need 4 to balance the array.The task is simple, we will find the sum of ...
Read MoreReferences to Functions in Perl
While using Perl script, this might happen if you need to create a signal handler so you can produce a reference to a function by preceding that function name with \& and to dereference that reference you simply need to prefix reference variable using ampersand &. Following is an example −Example#!/usr/bin/perl # Function definition sub PrintHash { my (%hash) = @_; foreach $item (%hash) { print "Item : $item"; } } %hash = ('name' => 'Tom', 'age' => 19); # Create a reference to above function. $cref = \&PrintHash; # Function call using reference. ...
Read MoreHow to use Formats in Perl?
In order to invoke a format declaration in Perl Script, we would use the write keyword −write EMPLOYEE;The problem is that the format name is usually the name of an open file handle, and the write statement will send the output to this file handle. As we want the data sent to the STDOUT, we must associate EMPLOYEE with the STDOUT filehandle. First, however, we must make sure that that STDOUT is our selected file handle, using the select() function.select(STDOUT);We would then associate EMPLOYEE with STDOUT by setting the new format name with STDOUT, using the special variable $~ or $FORMAT_NAME as ...
Read MoreCreate a Report Header using Perl
Sometime you would be interested in adding a header to your report. This header will be printed on top of each page. It is very simple to do this using Perl. Apart from defining a template you would have to define a header and assign it to $^ or $FORMAT_TOP_NAME variable −Example#!/usr/bin/perl format EMPLOYEE = =================================== @
Read MoreFind the Number of Maximum Product Quadruples in C++
Suppose we have one integer array with n elements. We have to find the maximum product of a quadruple in the array. So if the array is like [3, 5, 20, 6, 10], then final product is 6000, and elements in quadruple is 10, 5, 6, 20To solve this, we will follow these steps −Sort the array in ascending orderSuppose x be the product of last four elements, y be the product of first four elements, and z be the product of first two and second two elementsReturn the max of x, y and z.Example#include #include using namespace std; int ...
Read MoreFind the number of players who roll the dice when the dice output sequence is given in C++
Suppose we have a string S and a number X. There are M different players who roll the dice. one player keeps on rolling the dice until he gets a number other than X. Here in the string S, S[i] represents the number at ith roll of a dice. We have to find the value of M. One constraint is that the last character in S will never be X. So for example, if string is “3662123” and X = 6, the output will be 5. This can be described as follows −First player rolls and got 3Second player rolls, ...
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