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Program to generate random alphabets
  • Difficulty Level : Easy
  • Last Updated : 29 Jan, 2020
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Prerequisite : rand() and srand()
Given all alphabets in a character array, print a string of random characters of given size.

We will use rand() function to print random characters. It returns random integer values. This number is generated by an algorithm that returns a sequence of apparently non-related numbers each time it is called.

  1. A ubiquitous use of unpredictable random characters is in cryptography, which underlies most of the schemes which attempt to provide security in modern communications (e.g. confidentiality, authentication, electronic commerce, etc).
  2. Random numbers are also used in situations where “fairness” is approximated by randomization, such as selecting jurors and military draft lotteries.
  3. Random numbers have uses in physics such as electronic noise studies, engineering, and operations research. Many methods of statistical analysis, such as the bootstrap method, require random numbers.

Pseudo code :
1. First we initialize two character arrays, one containing all the alphabets and other of given size n to store result.

2. Then we initialize the seed to current system time so that every time a new random seed is generated.



3. Next, we use for loop till n and store random generated alphabets.

Below is C++ implementation of above approach :

C++




// CPP Program to generate random alphabets
#include <bits/stdc++.h>
using namespace std;
  
const int MAX = 26;
  
// Returns a string of random alphabets of
// length n.
string printRandomString(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 = "";
    for (int i = 0; i < n; i++) 
        res = res + alphabet[rand() % MAX];
      
    return res;
}
  
// Driver code
int main()
{
   srand(time(NULL));
   int n = 10;
   cout << printRandomString(n);
   return 0;
}

Java




// JAVA Program to generate random alphabets
import java.util.*;
  
class GFG
{
  
static int MAX = 26;
  
// Returns a String of random alphabets of
// length n.
static String printRandomString(int n)
{
    char []alphabet = { '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 = "";
    for (int i = 0; i < n; i++) 
        res = res + alphabet[(int) (Math.random() * 10 % MAX)];
      
    return res;
}
  
// Driver code
public static void main(String[] args)
{
    int n = 10;
    System.out.print(printRandomString(n));
}
}
  
// This code is contributed by Rajput-Ji

C#




// C# Program to generate random alphabets
using System;
  
class GFG
{
static int MAX = 26;
  
// Returns a String of random alphabets of
// length n.
static String printRandomString(int n)
{
    char []alphabet = { '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' };
  
    Random random = new Random();
    String res = "";
    for (int i = 0; i < n; i++) 
        res = res + alphabet[(int)(random.Next(0, MAX))];
      
    return res;
}
  
// Driver code
public static void Main()
{
    int n = 10;
    Console.Write(printRandomString(n));
}
}

Output :

jgyuihhlxb

This program will print different characters every time we run the code.

Want to learn from the best curated videos and practice problems, check out the C++ Foundation Course for Basic to Advanced C++ and C++ STL Course for foundation plus STL.
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