In the name of God;

Testlib has nice random functions, here I want to suggest some other ones. The first and the second random functions are available in testlib, but the rest are not.

1, $$$\text{rnd.next(l, r)}$$$, it will return a random number in range $$$l$$$ to $$$r$$$ with equal weights :

2, $$$\text{rnd.wnext(l, r, w)}$$$, it will return a random number in range $$$l$$$ to $$$r$$$ with monotonically increasing/decreasing weights depending on $$$w$$$ :

If $$$w = 0$$$ then it will be equal to $$$\text{rnd.next(l, r)}$$$.

If $$$w \gt 0$$$ :

If $$$w \lt 0$$$ :

3, $$$\text{rnd.cnext(l, r, c)}$$$, it will return a random number in range $$$l$$$ to $$$r$$$ :

If $$$c = 0$$$ then it will be equal to $$$\text{rnd.next(l, r)}$$$

If $$$c \gt 0$$$ :

If $$$c \lt 0$$$, (I couldn't find a accurate graph for it) :

4, $$$\text{rnd.cwnext(l, r, c1, c2)}$$$, it will return a random number in range $$$l$$$ to $$$r$$$ like $$$\text{rnd.cnext(l, r, c)}$$$, but its not centered around $$$\frac {r+l} 2$$$ :