# Program to generate random alphabets

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 :**

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 :

`// 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; ` `} ` |

*chevron_right*

*filter_none*

Output :

jgyuihhlxb

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

## Recommended Posts:

- C++ program to generate random number
- Generate a random permutation of 1 to N
- Generate random String of given size in Java
- Generate a random permutation of elements from range [L, R] (Divide and Conquer)
- JavaScript | Program to generate one-time password (OTP)
- Make alphabets using the elements of an array
- Count of alphabets having ASCII value less than and greater than k
- Remove consecutive alphabets which are in same case
- Count and Print the alphabets having ASCII value not in the range [l, r]
- Count and Print the alphabets having ASCII value in the range [l, r]
- random header in C++ | Set 1(Generators)
- Puzzle | Random Seating
- random header | Set 2 (Distributions)
- Find two numbers whose divisors are given in a random order
- Move all zeros to start and ones to end in an Array of random integers

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.