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.
- 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).
- Random numbers are also used in situations where “fairness” is approximated by randomization, such as selecting jurors and military draft lotteries.
- 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 :
- First we initialize two character arrays, one containing all the alphabets and other of given size n to store result.
- Then we initialize the seed to current system time so that every time a new random seed is generated.
- 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() * 100 % 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));
} } |
Javascript
<script> // JAVAscript Program to generate random alphabets let MAX = 26; // Returns a String of random alphabets of // length n. function printRandomString(n)
{ let 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' ];
let res = "" ;
for (let i = 0; i < n; i++)
{
res = res + alphabet[(Math.floor(Math.random() * 10) % MAX)];
}
return res;
} // Driver code let n = 10; document.write(printRandomString(n)); // This code is contributed by gfgking. </script> |
Python3
# Python program to generate random alphabets import random
# Returns a string of random alphabets of length n. def printRandomString(n):
MAX = 25
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' ]
res = ""
for i in range (n):
res = res + alphabet[random.randint( 0 , MAX )]
return res
n = 10
print (printRandomString(n))
# This code is contributed by lokeshmvs21. |
Output
urdfwootzr
Time Complexity: O(n)
Auxiliary Space: O(26)
This program will print different characters every time we run the code
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