The **`rand()` function** in C++ is used to generate random numbers; it will generate the same number every time we run the program. In order to *seed* the `rand()` function, `srand(unsigned int seed)` is used. The **`srand()` function** sets the initial point for generating the pseudo-random numbers.

Both of the functions are defined in the header:
``` c++
#include <cstdlib>
```
# Code

In the code below, the `rand()` function is used without seeding. Therefore, every time you press the *run* button, ​it generates the same number.


#include <iostream>
#include <cstdlib>
using namespace std;

int main() {
  int i = rand();
  cout << i;
}

Let's try using both of the functions together to see how it generates a different number after every click.
> Note: The standard practice is to use the return value of `time(0)` function as the seed. 

#include <iostream>
#include <cstdlib>
using namespace std;

int main() {
  srand(time(0));
  int i = rand();
  cout << i;
}

What are the rand and srand functions in C++?

Code