# Thread: how to loop the math.min and math.max

1. Registered User
Join Date
Dec 2009
Posts
12

## how to loop the math.min and math.max

the program that i want to create will first let the user input how many execution he want to perform and will determine the highest and lowest number that he inputted.

for example.

prompt: how many execution you want to perform?
i type: 5

prompt:input number:10
prompt:input number:8
prompt:input number:5
prompt:input number:0
prompt:input number:1

alert: the highest number is 10
alert: the smallest number is 0

i can do that by simply using this code.

<html>
<title>
Array example!
</title>
<body>
<script>
var inputs=new Array()
var z
var c
var b
for(z=0;z<=8;z++)
{
inputs[z]=prompt("Enter a number: ")
}

var a=inputs.slice(0,4)

c=Math.min(inputs[0],inputs[1],inputs[2],inputs[3],inputs[4],inputs[5],inputs[6])
b=Math.max(inputs[0],inputs[1],inputs[2],inputs[3],inputs[4],inputs[5],inputs[6])

document.write(inputs[0])
document.write("<br>"+inputs[1])
document.write("<br>"+inputs[2])
document.write("<br>"+inputs[3])
document.write("<br>"+inputs[4])
document.write("<br>"+inputs[5])
document.write("<br>"+inputs[6])
document.write("<br>"+inputs[7])
document.write("<br>"+inputs[8])

alert(b+" is the highest number and " +c+ " is the smallest number")

</script>
</body>
</html>

but it only allows for the up to inputs[6] and the code is very long. i think i can use looping in it. but i dont know to use looping in math.min and math.max.

2. Registered User+
Join Date
Feb 2006
Posts
2,930
// Get all the numbers at once in the prompt string,
// and use string.split or match to get the numbers into an array.
//
Code:
```var min= Infinity, max= -Infinity, arr, str= '';
while(str== ''){
str= prompt('Enter the numbers to compare, separated by commas','');
arr= str.match(/(\.\d+|\d+(\.\d+)?)/g) || '';
}```
// now you can loop through each member of arr and test max and min:
//
Code:
```for(var i=0,L=arr.length;i<L;i++){
max= Math.max(arr[i], max)
min= Math.min(arr[i], min);
}
alert('Range is from '+min+' to '+max);```
// You can skip the loop and use Math.max and Math.min
// directly on an array of numbers,
// but you need to apply the methods to the arrays:
//
Code:
```max= Math.max.apply('', arr);
min= Math.min.apply('', arr);
alert('Range is from '+min+' to '+max);```
// Or the simplest way, you could sort the array by value
// and return the first and last members:
//
Code:
```arr= arr.sort(function(a, b){return a-b});
alert('Range is from '+arr.shift()+' to '+arr.pop());```

3. Registered User
Join Date
Dec 2009
Posts
12
hi mrhoo youre code is good, but i cant understand it very well, can you please explain it a little bit more?

im very interested in this code

arr= arr.sort(function(a, b){return a-b});
alert('Range is from '+arr.shift()+' to '+arr.pop());

but i cant apply it on my codes.

by the way do you know a method that will get the first and last in the .sort?

i have my newly revise code here it is.

<html>
<title>
Array example!
</title>
<body>
<script>
var inputs=new Array()
var z
var c
var b
for(z=0;z<=8;z++)
{
inputs[z]=prompt("Enter a number: ")
}

c=inputs.slice(0,4)

document.write(inputs+"<br>");

a=inputs.reverse()
document.write(a+"<br>");

b=c.sort()
document.write(b+"<br>")

d=Math.min(b)
e=Math.max(b)

</script>
</body>
</html>

by using sort it will arrange the numbers from highest to lowest, but i dont know any method that will get the first and last digits so that it will determine the highest and lowest from the slice.
Last edited by cary1234; 02-20-2010 at 08:40 PM.

4. Registered User+
Join Date
Feb 2006
Posts
2,930
var array=[1,3,5,2,4];
array.sort(function(a,b){return a-b});

// array is now[1,2,3,4,5]

var min=array.shift()
// shift removes and returns the first item (1)
var max=array.pop()
// pop removes and returns the last item (5)

5. Registered User
Join Date
Dec 2009
Posts
12

## Thank you!

it works great!

thank you very much.