Select random letters in C++

This post will discuss how to select random letters in C++.

A common solution to generate a random number between 0 and RAND_MAX is using the rand() function, defined in the <cstdlib> header. We can use it to generate a random letter between some specific range, as shown below for ASCII lowercase alphabet range a-z:

#include <iostream>

#include <ctime>

int main()

{

srand(time(NULL));

char ch = 'a' + rand() % 26;

std::cout << ch << std::endl;

return 0;

}

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Don’t forget to pass a seed to the function srand(), preferably the current time. To generate a random uppercase letter, do like:

#include <iostream>

int main()

{

char ch = 'A' + rand() % 26;

std::cout << ch << std::endl;

return 0;

}

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We can easily extend the above solution to generate values in ranges a-z and A-Z:

#include <iostream>

#include <ctime>

char randomLetter() {

int r = rand() % 52;

char base = (r < 26) ? 'A' : 'a';

return (char) (base + r % 26);

}

int main()

{

srand(time(NULL));

char ch = randomLetter();

std::cout << ch << std::endl;

return 0;

}

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Finally, you can generate a random letter from ASCII alphanumeric range or any other specific character range as follows:

#include <iostream>

#include <ctime>

int main()

{

srand(time(NULL));

std::string alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

char ch = alphabet[rand() % alphabet.size()];

std::cout << ch << std::endl;

return 0;

}

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That’s all about selecting random letters in C++.

Select random letters in C++

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