JS generates a range of random number "four kinds of situation detailed" _javascript skills

Objective:

JS does not have ready-made functions, can directly generate a specified range of random numbers.

But it has a function: math.random () This function can generate a random number of [0,1].

With it, we can generate random numbers within a specified range.

When it comes to scope, there is a problem with the boundary value. This will include four different scenarios:

1) Min≤r≤max (generally this relatively common)

2) Min≤r < Max

3 min < R≤max

4 min < R < Max

First, Min≤r≤max

function Randomnumboth (Min,max) {
      var Range = max-min;
      var Rand = Math.random ();
      var num = Min + math.round (Rand * Range); Rounding return
      num;
}

Second, Min≤r < Max

function Randomnum (Min, Max) {
      var Range = max-min;
      var Rand = Math.random ();
      var num = Min + math.floor (Rand * Range); to return
      num;

Third, Min < R≤max

function Randomnum (Min, Max) {
      var Range = max-min;
      var Rand = Math.random ();
      if (Math.Round (Rand * Range) ==0) {return       
        Min + 1;
      }
      var num = Min + math.round (Rand * Range);
      return num;
}

Iv. min < r < Max

function Randomnum (Min, Max) {
      var Range = max-min;
      var Rand = Math.random ();
      if (Math.Round (Rand * Range) ==0) {return
        Min + 1;
      } else if (Math.Round (Rand * Max) ==max)
      {
        index++;
        return Max-1;
      } else{
        var num = Min + math.round (Rand * Range)-1;
        return num;
      }
 }

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