Prompt user to Input Numbers in Array and then Sum it using JavaScript

Question

This works fine if I sum numbers in JavaScript in an Array. But when I ask their input from User then they are printed as if the numbers are in string. Kindly help me in finding the flaw in my code.

var tArr = [];

for(var f = 1;f<=4;f++)                                                           
{   
    // tArr.push(f);  
    var z = prompt("Enter numbers for Sum");   
    tArr.push(z);                              

}   
var r = parseInt(tArr);   
alert(tArr);       

var summ = 0;      
for(var w = 0; w< tArr.length; w++)     
{   
    summ += tArr[w];   
}   
console.log(summ);

Amardeep Bhowmick · Accepted Answer · 2018-08-24 20:55:44Z

2

To convert all values to number just do +tArr[w] then sum it. The +tArr[w] will coerce each value into a number instead of a string and hence will sum it instead of concatenating it.

var tArr = [];

for(var f = 1;f<=4;f++)                                                           
{   
    // tArr.push(f);
    var z = prompt("Enter numbers for Sum");   
    tArr.push(z);                              

}   
//var r = parseInt(tArr); This line is not doing anything.
alert(tArr);       

var summ = 0;      
for(var w = 0; w< tArr.length; w++)     
{   
    summ += +tArr[w];   
}   
console.log(summ);

answered Aug 24, 2018 at 20:55

Amardeep Bhowmick

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3 Comments

Jia Over a year ago

But why are they being taken as strings?

Amardeep Bhowmick Over a year ago

Because window.prompt() returns a string, which is added to the array tArr. While iterating the strings are converted to number by adding a + before it. developer.mozilla.org/en-US/docs/Web/API/Window/prompt

Jia Over a year ago

Ohkay..! Thanks alot Amardeep!

Mohammad · Accepted Answer · 2018-10-15 08:08:43Z

0

var sum=0;
var len=(Number(prompt("Enter len of array")));
var ar=new Array();

for(var i=0;i<len;i++){
  ar.push(Number(prompt("Enter array elements:"+ar[i])));
}
for(var i=0;i<len;i++){
  sum+=ar[i];
}

document.write(sum+" ");

edited Oct 15, 2018 at 8:08

Mohammad

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answered Oct 15, 2018 at 7:47

Anand Singh

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