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Articles on Trending Technologies
Technical articles with clear explanations and examples
C++ program to get the Sum of series: 1 – x^2/2! + x^4/4! -.... upto nth term
In this tutorial, we will be discussing a program to get the sum of series 1 – x^2/2! + x^4/4! … upto nth term.For this we will be given with the values of x and n. Our task will be to calculate the sum of the given series upto the given n terms. This can be easily done by computing the factorial and using the standard power function to calculate powers.Example#include #include //calculating the sum of series double calc_sum(double x, int n){ double sum = 1, term = 1, fct, j, y = 2, m; int ...
Read MoreC++ program to generate random alphabets
In this tutorial, we will be discussing a program to generate random alphabets.For this, we will have a fixed size of array/string and use the rand() function to generate a random string of alphabets.Example#include using namespace std; const int MAX = 26; //generating a string of random alphabets string gen_random(int n){ char alphabet[MAX] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' }; string res ...
Read MoreC++ program to generate CAPTCHA and verify user
In this tutorial, we will be discussing a program to generate CAPTCHA and verify user.For this, we will provide the user with a random string and ask him to reenter the same string. Then it has to be checked if the given and the input string matches.The CAPTCHA should be completely random system generated consisting of a-z, AZ and 0-9.Example#include using namespace std; //checks if the strings are same bool check_string(string &captcha, string &user_captcha){ return captcha.compare(user_captcha) == 0; } //generates a random string as Captcha string gen_captcha(int n){ time_t t; srand((unsigned)time(&t)); char *chrs = "abcdefghijklmnopqrstuvwxyzABCDEFGHI" "JKLMNOPQRSTUVWXYZ0123456789"; ...
Read MoreWhat is POD in Perl?
Pod is a simple-to-use markup language used for writing documentation for Perl, Perl programs, and Perl modules. There are various translators available for converting Pod to various formats like plain text, HTML, man pages, and more. Pod markup consists of three basic kinds of paragraphs −Ordinary Paragraph − You can use formatting codes in ordinary paragraphs, for bold, italic, code-style , hyperlinks, and more.Verbatim Paragraph − Verbatim paragraphs are usually used for presenting a codeblock or other text which does not require any special parsing or formatting, and which shouldn't be wrapped.Command Paragraph − A command paragraph is used for ...
Read MoreThe kill() Function in Perl
Perl kill('KILL', (Process List)) function can be used to terminate a pseudo-process by passing it the ID returned by fork().Note that using kill('KILL', (Process List)) on a pseudo-process() may typically cause memory leaks, because the thread that implements the pseudo-process does not get a chance to clean up its resources.You can use kill() function to send any other signal to target processes, for example following will send SIGINT to a process IDs 104 and 102 −#!/usr/bin/perl kill('INT', 104, 102); 1;
Read MoreThe system() Function in Perl
You can use system() Perl function to execute any Unix command, whose output will go to the output of the perl script. By default, it is the screen, i.e., STDOUT, but you can redirect it to any file by using redirection operator > −#!/usr/bin/perl system( "ls -l") 1;When above code is executed, it lists down all the files and directories available in the current directory −drwxr-xr-x 3 root root 4096 Sep 14 06:46 9-14 drwxr-xr-x 4 root root 4096 Sep 13 07:54 android -rw-r--r-- 1 root root 574 Sep 17 15:16 index.htm drwxr-xr-x 3 544 401 4096 Jul 6 16:49 MIME-Lite-3.01 ...
Read MoreBackstick Operator in Perl
This simplest way of executing any Unix command in Perl Program is by using backstick operator. You simply put your command inside the backstick operator, which will result in execution of the command and returns its result which can be stored as follows −#!/usr/bin/perl @files = `ls -l`; foreach $file (@files) { print $file; } 1;When the above code is executed, it lists down all the files and directories available in the current directory −drwxr-xr-x 3 root root 4096 Sep 14 06:46 9-14 drwxr-xr-x 4 root root 4096 Sep 13 07:54 android -rw-r--r-- 1 root root 574 Sep 17 ...
Read MoreWhat are Perl Modules?
A Perl module is a reusable package defined in a library file whose name is the same as the name of the package with a .pm as extension.A Perl module file called Foo.pm might contain statements like this.#!/usr/bin/perl package Foo; sub bar { print "Hello $_[0]" } sub blat { print "World $_[0]" } 1;Few important points about Perl modulesThe functions require and use will load a module.Both use the list of search paths in @INC to find the module.Both functions require and use call the eval function to process the code.The 1; at the bottom causes eval to evaluate to TRUE (and thus not ...
Read MoreWhat is the data type of a lambda expression in Java?
The lambda expressions have a very simple, precise syntax and provide flexibility to specify the datatypes for the function parameters. Its return type is a parameter -> expression body to understand the syntax, we can divide it into three parts.Parameters : These are function method parameters and match with the signature of a function defined in the functional interface. Defining the data-type of parameters is optional but the number of parameters can match with the defined signatures in the interface.Expression Body : This is either a single statement or collection of statements that represent the function definition. Defining the data-type ...
Read MoreHow to use Cookies in CGI in Perl?
HTTP protocol is a stateless protocol. But for a commercial website it is required to maintain session information among different pages. For example one user registration ends after transactions which spans through many pages. But how to maintain user's session information across all the web pages?In many situations, using cookies is the most efficient method of remembering and tracking preferences, purchases, commissions, and other information required for better visitor experience or site statistics.How It WorksYour server sends some data to the visitor's browser in the form of a cookie. The browser may accept the cookie. If it does, it is ...
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