What is seed value in srand function ? - C++

Question

To use rand() function properly, srand() function is used which provides seed value to the rand() function. My question is what does providing a seed value to rand() function means and why does rand() works properly if seed value is provided to it ?

Answer 1

Imagine you can actually see the algorithm behind rand() function, e.g.

rand() takes a value and perform multiplication, division, etc. We call that original value as a seed.

srand() function alters that value which is used by rand() to perform the algorithm of generating random numbers. This means that srand() alters the seed.

e.g.

srand(1);
cout << rand();

//outputs first random number

srand(2);
cout << rand();

//outputs second random number

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In order for the seed to be really randomises, we utilise time(), since the system time alternates every second.

srand(time(0));

Answer 2

Thanks for the response. I have a better understanding of it now.