PROGRAM ZA USTVARJANJE CAPTCHA IN PREVERJANJE UPORABNIKA

A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) je test za ugotavljanje, ali je uporabnik človek ali ne.
Naloga je torej vsakič ustvariti edinstveno CAPTCHA in ugotoviti, ali je uporabnik človek ali ne, tako da uporabnika prosimo, da vnese isto CAPTCHA, kot je bila ustvarjena samodejno, in preverite uporabniški vnos z ustvarjeno CAPTCHA.
Primeri:

CAPTCHA: x9Pm72se Input: x9Pm62es Output: CAPTCHA Not Matched CAPTCHA: cF3yl9T4 Input: cF3yl9T4 Output: CAPTCHA Matched

Nabor znakov za ustvarjanje CAPTCHA je shranjen v matriki znakov chrs[], ki vsebuje (a-z A-Z 0-9), zato je velikost chrs[] 62.
Za generiranje edinstvenega CAPTCHA vsakič, ko je ustvarjeno naključno število, uporabite funkcijo rand() (rand()%62), ki generira naključno število med 0 in 61 in ustvarjeno naključno število se vzame kot indeks za niz znakov chrs[], tako ustvari nov znak captcha[] in ta zanka se izvede n (dolžina CAPTCHA)-krat, da se ustvari CAPTCHA dane dolžine.

Algoritem:

Najprej deklarirajte in definirajte funkcijo checkCaptcha(), ki sprejme dva parametra niza in vrne logično vrednost.
Znotraj funkcije checkCaptcha() primerjajte oba parametra niza s funkcijo compare() in vrnite true, če sta enaka; sicer vrne false.
Deklarirajte in definirajte funkcijo generateCaptcha(), ki sprejme celoštevilski parameter in vrne vrednost niza.
Znotraj funkcije generateCaptcha() inicializirajte časovno spremenljivko s funkcijo time() in zaženite generator naključnih števil s funkcijo srand().
Deklarirajte matriko znakov, ki vsebuje vse znake, ki bodo vključeni v CAPTCHA, in jo dodelite spremenljivki kazalca char.
Ustvarite naključni niz CAPTCHA podane dolžine z večkratnim dodajanjem naključnih znakov iz niza znakov v spremenljivko niza s funkcijo push_back().
Vrni ustvarjeni niz CAPTCHA.
Znotraj funkcije main() deklarirajte spremenljivko niza z imenom captcha in pokličite funkcijo generateCaptcha() z dolžino 9, da ustvarite naključni niz CAPTCHA.
Natisnite ustvarjeni niz CAPTCHA na konzoli.

CPP

// C++ program to automatically generate CAPTCHA and // verify user #include    using namespace std; // Returns true if given two strings are same bool checkCaptcha(string& captcha string& user_captcha) {  return captcha.compare(user_captcha) == 0; } // Generates a CAPTCHA of given length string generateCaptcha(int n) {  time_t t;  srand((unsigned)time(&t));  // Characters to be included  char* chrs = 'abcdefghijklmnopqrstuvwxyzABCDEFGHI'  'JKLMNOPQRSTUVWXYZ0123456789';  // Generate n characters from above set and  // add these characters to captcha.  string captcha = '';  while (n--)  captcha.push_back(chrs[rand() % 62]);  return captcha; } // Driver code int main() {  // Generate a random CAPTCHA  string captcha = generateCaptcha(9);  cout << captcha;  // Ask user to enter a CAPTCHA  string usr_captcha;  cout << 'nEnter above CAPTCHA: ';  cin >> usr_captcha;  // Notify user about matching status  if (checkCaptcha(captcha usr_captcha))  printf('nCAPTCHA Matched');  else  printf('nCAPTCHA Not Matched');  return 0; }

Java

// Java pprogram to automatically generate CAPTCHA and // verify user import java.util.*; import java.io.*; class GFG {    // Returns true if given two strings are same  static boolean checkCaptcha(String captcha String user_captcha)  {  return captcha.equals(user_captcha);  }    // Generates a CAPTCHA of given length  static String generateCaptcha(int n)  {  //to generate random integers in the range [0-61]  Random rand = new Random(62);     // Characters to be included  String chrs = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';    // Generate n characters from above set and  // add these characters to captcha.  String captcha = '';  while (n-->0){  int index = (int)(Math.random()*62);  captcha+=chrs.charAt(index);  }    return captcha;  }    // Driver code  public static void main(String[] args)throws IOException  {  BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));    // Generate a random CAPTCHA  String captcha = generateCaptcha(9);  System.out.println(captcha);    // Ask user to enter a CAPTCHA  System.out.println('Enter above CAPTCHA: ');  String usr_captcha = reader.readLine();    // Notify user about matching status  if (checkCaptcha(captcha usr_captcha))  System.out.println('CAPTCHA Matched');  else  System.out.println('CAPTCHA Not Matched');  } } // This code is contributed by shruti456rawal

Python3

# Python program to automatically generate CAPTCHA and # verify user import random # Returns true if given two strings are same def checkCaptcha(captcha user_captcha): if captcha == user_captcha: return True return False # Generates a CAPTCHA of given length def generateCaptcha(n): # Characters to be included chrs = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789' # Generate n characters from above set and # add these characters to captcha. captcha = '' while (n): captcha += chrs[random.randint(1 1000) % 62] n -= 1 return captcha # Driver code # Generate a random CAPTCHA captcha = generateCaptcha(9) print(captcha) # Ask user to enter a CAPTCHA print('Enter above CAPTCHA:') usr_captcha = input() # Notify user about matching status if (checkCaptcha(captcha usr_captcha)): print('CAPTCHA Matched') else: print('CAPTCHA Not Matched') # This code is contributed by shubhamsingh10

using System; using System.Text; class GFG {  // Returns true if given two strings are same  static bool CheckCaptcha(string captcha string user_captcha)  {  return captcha.Equals(user_captcha);  }  // Generates a CAPTCHA of given length  static string GenerateCaptcha(int n)  {  // to generate random integers in the range [0-61]  Random rand = new Random();  // Characters to be included  string chrs = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';  // Generate n characters from above set and  // add these characters to captcha.  StringBuilder captcha = new StringBuilder();  while (n-- > 0)  {  int index = rand.Next(62);  captcha.Append(chrs[index]);  }  return captcha.ToString();  }  // Driver code  static void Main(string[] args)  {  // Generate a random CAPTCHA  string captcha = GenerateCaptcha(9);  Console.WriteLine(captcha);  // Ask user to enter a CAPTCHA  Console.WriteLine('Enter above CAPTCHA: ');  string usr_captcha = Console.ReadLine();  // Notify user about matching status  if (CheckCaptcha(captcha usr_captcha))  Console.WriteLine('CAPTCHA Matched');  else  Console.WriteLine('CAPTCHA Not Matched');  } }

JavaScript

// JavaScript program to automatically generate CAPTCHA and // verify user // Returns true if given two strings are same function checkCaptcha(captcha user_captcha) { return captcha.localeCompare(user_captcha) == 0; } // Generates a CAPTCHA of given length function generateCaptcha(n) { // Characters to be included const chrs = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'; let captcha = ''; for (let i = 0; i < n; i++) { captcha += chrs[(Math.floor(Math.random() * chrs.length))]; } return captcha; } // Driver code function main() { // Generate a random CAPTCHA const captcha = generateCaptcha(9); console.log(captcha); // Ask user to enter a CAPTCHA const usr_captcha = prompt('Enter above CAPTCHA:'); // Notify user about matching status if (checkCaptcha(captcha usr_captcha)) console.log('CAPTCHA Matched'); else console.log('CAPTCHA Not Matched'); } main();

Izhod:

CAPTCHA: cF3yl9T4 Enter CAPTCHA: cF3yl9T4 CAPTCHA Matched

Časovna zapletenost: O(n)
Kompleksnost prostora: O(1)

Ustvari kviz

TechCodeview

Program za ustvarjanje CAPTCHA in preverjanje uporabnika