how to use math.random and math.floor

Question

like it says in the title.

Answer 1

Math.random() returns any number:
- between 0 and 1 (0.43, 0.99, 0.45)
- zero (0)
- not including ONE (1)

So Math.random() * 2 generates any number between 0 and 2, including 0 but not 2 (0.34, 1.78, 1.99)

You can then wrap the generated random number inside Math.floor() to remove the decimals

Math.floor(Math.random() * 2);

Math.random() is evaluated first, say we got 1.99

Math.floor() is evaluated next, it will ignore the decimals and the result is 1

So if you do random() * 5 wrapped inside floor(), you're generating random whole numbers from 0 to 4 only

Answer 2

/* Math.floor(x) returns the integer less than or equal to the input number */

var x = 2.3;
console.log(Math.floor(x));
//prints 2

var x = Math.random();
// x can be any decimal between 0 and 1

Answer 3

/*Samuel, I like your example! i just modified that you wrote. Now code show the color name, not just numbers.*/
var variable = ["infrared waves","red", "orange","yellow","green","light blue","blue","violet","ultraviolet"];

var rnd = Math.floor (Math.random () * (variable.length));

switch (rnd){
case 0 : document.write("infrared");
break;
case 1 : document.write("red");
break;
case 2 : document.write("orange");
break;
case 3 : document.write("yellow");
break;
case 4 : document.write("green");
break;
case 5 : document.write("light blue");
break;
case 6 : document.write("blue");
break;
case 7 : document.write("violet");
break;
case 8 : document.write("ultraviolet");
break;
}