How to generate random words in solidity based on a string of letters - random

Question

I would like to make a word generation function based on the letters of the alphabet, but I don't know how to proceed. I would like to generate 12 words
string letters public = "abcdefghijklmnopqrstuvwxyz"
But I don't understand how I could proceed in solidity to generate
For numbers, I do this
pragma solidity ^0.8.0;
contract RandomNumbers{
function random(uint number) public view returns(uint){
return uint(keccak256(abi.encodePacked(block.timestamp,block.difficulty,
msg.sender))) % number;
}
}
But for words, I don't know how I could proceed

Answer 1

contract MiniTest {
string public letters = "abcdefghijklmnopqrstuvwxyz";
// I needed to add this to the random function to generate a different random number
uint counter =1;
// size is length of word
function randomString(uint size) public payable returns(string memory){
bytes memory randomWord=new bytes(size);
// since we have 26 letters
bytes memory chars = new bytes(26);
chars="abcdefghijklmnopqrstuvwxyz";
for (uint i=0;i<size;i++){
uint randomNumber=random(26);
// Index access for string is not possible
randomWord[i]=chars[randomNumber];
}
return string(randomWord);
}
function random(uint number) public payable returns(uint){
counter++;
return uint(keccak256(abi.encodePacked(block.timestamp,block.difficulty,
msg.sender,counter))) % number;
}
}
I slightly changed the random function because it was generating the same random number so the result for 5 characters was like "jjjjj".
string in solidity has no index property. so we have to work with bytes and then convert it to string
Here is the proof of work:

Answer 2

I just improved the answer of #Yilmaz to make the functions view only from payable.
There is an additional function called roll() which outputs true or false based on chance. The 101 within roll() can be altered to 10001 to make the odds down to 0.01% or you can make it dynamic by passing a parameter in place of 101.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;
contract Random {
//Roll Chance
function roll(uint256 number) public view returns (bool) {
uint256 d = uint256(
keccak256(abi.encodePacked(block.difficulty, block.timestamp))
) % 101;
if (d <= number) return true;
return false;
}
//Random Number Generator
function random(uint256 number, uint256 counter)
public
view
returns (uint256)
{
return
uint256(
keccak256(
abi.encodePacked(
block.timestamp,
block.difficulty,
msg.sender,
counter
)
)
) % number;
}
//Random String Generator (Max length 14)
function randomString(uint256 length) public view returns (string memory) {
require(length <= 14, "Length cannot be greater than 14");
require(length >= 1, "Length cannot be Zero");
bytes memory randomWord = new bytes(length);
// since we have 62 Characters
bytes memory chars = new bytes(62);
chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
for (uint256 i = 0; i < length; i++) {
uint256 randomNumber = random(62, i);
// Index access for string is not possible
randomWord[i] = chars[randomNumber];
}
return string(randomWord);
}
}
I hope this Helps.