Random

Published Aug 3, 2021Updated Mar 27, 2023
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C++ has a std::rand() function from cstdlib library that generates a random number.

For example, if we add #include <cstdlib>, we can use the std::rand() function:

std::cout << std::rand() << "\n";
std::cout << std::rand() << "\n";
std::cout << std::rand() << "\n";

It would output something like:

1804289383
846930886
1681692777

Using Modulo

A lot of the times, we don’t just want any random number. Suppose We want a random number from 0-9.

int answer = std::rand() % 10;

The % is the modulo symbol that returns the remainder.

Seeding the Random Number Generator

For our program to work, we need to get a different random number for each execution.

To do so, we need to add this line of code before the declaration of answer:

srand(time(NULL));

This sets the “seed” of the random number generator.

Codebyte Example

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