# 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.

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