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Sum values from an Array, JavaScript

Prompting the user for many inputs, storing it in an array, then printing summation , average, largest number, smallest number and bigger number than mean number. I have defined a JavaScript variables called magicnumber which is a new Array , and print the value of array, like this:

 var magicnumber = []; mymagicNumber(); function mymagicNumber() { //Specify the size of array var size = parseInt(prompt("How many data values do you need have?")); for (var i = 1; i <= size; i++) { //sorted in array var num = parseInt(magicnumber.push(prompt("Enter data value number " + i))); var s = magicnumber.join(', '); } //Display array element document.getElementById("demo1").innerHTML = "Your data : " + s + "<br>"; } 
 <div id="demo1"></div> 

how I can summation it?

Here are 2 more ways to find the summation, without using for loop.

 var magicnumber = []; function mymagicNumber() { //Specify the size of array var size = parseInt(prompt("How many data values do you need have?")); for (var i = 1; i <= size; i++) { //sorted in array var num = magicnumber.push(parseInt(prompt("Enter data value number " + i))); } var data = magicnumber.join(', '); var s1 = magicnumber.reduce(function(acc, val) { return acc + val; }); var s2 = eval(magicnumber.join("+")); //Display array element document.getElementById("demo1").innerHTML = "Your data : " + data + "<br>"; document.getElementById("demo2").innerHTML = "Sum is: " + s1 + "<br>"; document.getElementById("demo3").innerHTML = "Sum is: " + eval(s2) + "<br>"; } mymagicNumber(); 
 <div id="demo1"></div> <div id="demo2"></div> <div id="demo3"></div> 

You can use Array#reduce() to get the sum

 var magicnumber = []; mymagicNumber(); function mymagicNumber() { //Specify the size of array var size = parseInt(prompt("How many data values do you need have?")); for (var i = 1; i <= size; i++) { var promptValue = prompt("Enter data value number " + i); magicnumber.push(+promptValue); } var sum = magicnumber.reduce((a,b)=>{return a+b},0); //Display array element document.getElementById("demo1").innerHTML = "Your data : " + magicnumber.join(', '); document.getElementById("sum").innerHTML = "The sum : " + sum; } 
 <div id="demo1"></div> <div id="sum"></div> 

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