Print Sum of Array Values

Question

I am trying to find and print the total of the array, but it only prints the array. Any suggestions on where I went wrong?

var c = new Array(
    "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
    "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", 
    "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", 
    "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", 
    "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", 
    "62", "63", "64", "65", "66", "67", "68", "69", "70", "71", "72", "73", 
    "74", "75", "76", "77", "78", "79", "80", "81", "82", "83", "84", "85", 
    "86", "87", "88", "89", "90", "91", "92", "93", "94", "95", "96", "97", 
    "98", "99", "100"
) 

var total = 0;

for ( var i = 0; i < 100; ++i )
{

    total += c [ i ];
}

document.writeln( "<p>The total of array c is: " + total + "</p>" );

user1864610 · Accepted Answer · 2015-03-07 03:16:27Z

1

You have an array of strings, so Javascript uses the + operator as a concatenation. You need to change the values to numbers first.

Try this:

for ( var i = 0; i < 100; ++i ) {
  total += (+c[i]);
}

The unary + forces Javascript to treat the value as a number;

There's a Fiddle here

answered Mar 7, 2015 at 3:16

user1864610

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2 Comments

Joshua Dwire Over a year ago

Another alternative is to use parseInt(c[i], 10).

Rebecca Richardson Over a year ago

1st: Thank you for making my original post look like code. & that worked perfectly!!! I haven't came across that technique yet, but nothing I could find in the book was working. Thanks.

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