Random function generator C++

I want to generate a random number in C++ based on known distribution.

Here is the problem. I rolled a dice (say) 6 times, and I record a four for 3 times, and an one for 1 times, and a two for 2 times. So four=3/6, one=1/6, two=2/6

Is there a library function that I could use which generates a random number based on the above distribution?

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If not, do you think it is valid for me to simply do

int i= ran()%5;
if (i is in the range of 0 to 2)
{
  //PICK FOUR
}

else if (i is in the range of 3 to 4)
{
  // PICK ONE
}

else 
{
   // PICK TWO
}