Uneven Distribution in rand() ( C language )

Question

I wanted to see if there is any way to generate random numbers with uneven distribution which I would like to customize.
for example:
In 100 generated numbers I would like to have :
10 A
20 B
40 C
10 D
15 E
5 F
And I wanted to say that I'm new to programming so try to help me with your simple answers. Really Really Thank You.

Answer 1

This is a pretty simple, yet often highly effective solution for problems like this:

char *samples = "AABBCCDDEEFFFFF";

char randomSample() {
  return sample[rand() % strlen(samples)];
}