# Thread: Sum the numbers of an array

1. Shi
Registered User
Join Date
Apr 2017
Posts
14

## Sum the numbers of an array

Hello!

I wrote a function that should sum up all the numbers that are contained within an array which just was created.
In the mySum function I use the variable "sumOfNumbers" to count all the numbers together. But I do get out NaN.

I checked with typeof, the array is an array(object), the numbers I extract are numbers, the "sumOfNumbers" variable I created as a number. Why is it not able to count the numbers to the variable?
I tried to use Number() to make sure what is counted together are numbers, but does not seem to work.

Code:
// range to array
function myRange(start, end) {
var numberList = [];

for (var i = start; i <= end; i++) {
numberList[i] = i;
}
return numberList;
}

//sum array numbers
function mySum(numbers) {
var numbers = numbers;
var sumOfNumbers = 0;

for (var i = 0; i <= numbers.length-1; i++) {
var c = numbers[i];
sumOfNumbers += c;   <-- becomes NaN
}
return sumOfNumbers;
}

var x = mySum(myRange(5, 7));
console.log(x);

2. Registered User
Join Date
Mar 2011
Posts
125
It doesn't work because
Code:
// range to array
function myRange(start, end) {
var numberList = [];
for (var i = start; i <= end; i++) {
numberList[i] = i;			// <-- start at position i
}
return numberList;
};

var arr = myRange(5, 7);			// arr = [undefined,undefined,undefined,undefined,undefined,5,6,7]
mySum(arr);

function mySum(numbers) {
var numbers = numbers;
var sumOfNumbers = 0;

for (var i = 0; i <= numbers.length-1; i++) {
var c = numbers[i];
sumOfNumbers += c;   //<-- becomes NaN, because adding to undefined
}
return sumOfNumbers;
};
This does what you want
Code:
function myRange(start, end) {
var numberList = [];
for (var i = start; i <= end; i++) {
numberList.push(i);
}
return numberList;
};

function mySum(numbers) {
var sumOfNumbers = 0;
for (var i = 0; i < numbers.length; i++) {
sumOfNumbers += numbers[i];
}
return sumOfNumbers;
};

var arr = myRange(5, 7);
mySum(arr);

3. or prototype it...

Code:
Array.prototype.array_sum = function(){
// sum the array elements 0 to nth, does not count associative named arrays
for( this['sum']=0, tc=0; tc<this.length; tc++ ) this['sum'] += this[tc];
this['count'] = this.length;
}
Then use it like...

myArray.array_sum();
then to get the sum of it, you use sum = myArray['sum'];

Code:
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
arr.array_sum();
console.log("> " + arr + " = " + arr['sum'] );
outputs to the console log (F12 open close, click console log tab )
Code:
> 1,2,3,4,5,6,7,8,9,10 = 55

4. Shi
Registered User
Join Date
Apr 2017
Posts
14

There are currently 1 users browsing this thread. (0 members and 1 guests)

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•

"

"

## X vBulletin 4.2.2 Debug Information

• Page Generation 0.31953 seconds
• Memory Usage 2,859KB
• Queries Executed 14 (?)
Template Usage (33):
• (6)bbcode_code
• (1)footer
• (1)forumjump
• (1)forumrules
• (1)gobutton
• (4)memberaction_dropdown
• (1)navbar
• (1)navbar_moderation
• (1)navbar_noticebit
• (1)navbar_tabs
• (2)option
• (4)postbit
• (4)postbit_onlinestatus
• (4)postbit_wrapper
• (1)spacer_close
• (1)spacer_open
• (1)tagbit_wrapper

Phrase Groups Available (6):
• global
• inlinemod
• postbit
• posting
• reputationlevel
Included Files (26):
• ./global.php
• ./includes/class_bootstrap.php
• ./includes/init.php
• ./includes/class_core.php
• ./includes/config.php
• ./includes/functions.php
• ./includes/class_friendly_url.php
• ./includes/class_hook.php
• ./includes/class_bootstrap_framework.php
• ./vb/vb.php
• ./vb/phrase.php
• ./includes/functions_calendar.php
• ./includes/functions_bigthree.php
• ./includes/class_postbit.php
• ./includes/class_bbcode.php
• ./includes/functions_reputation.php
• ./includes/functions_notice.php
• ./packages/vbattach/attach.php
• ./vb/types.php
• ./vb/cache.php
• ./vb/cache/db.php
• ./vb/cache/observer/db.php
• ./vb/cache/observer.php

Hooks Called (71):
• init_startup
• friendlyurl_resolve_class
• init_startup_session_setup_start
• database_pre_fetch_array
• database_post_fetch_array
• init_startup_session_setup_complete
• global_bootstrap_init_start
• global_bootstrap_init_complete
• cache_permissions
• fetch_foruminfo
• global_state_check
• global_bootstrap_complete
• global_start
• style_fetch
• global_setup_complete
• strip_bbcode
• friendlyurl_clean_fragment
• friendlyurl_geturl
• forumjump
• cache_templates
• cache_templates_process
• template_register_var
• template_render_output
• fetch_template_start
• fetch_template_complete
• parse_templates
• notices_check_start
• notices_noticebit
• process_templates_complete
• friendlyurl_redirect_canonical
• bbcode_fetch_tags
• bbcode_create
• postbit_factory
• postbit_display_start
• postbit_imicons
• bbcode_parse_start
• bbcode_parse_complete_precache
• bbcode_parse_complete
• postbit_display_complete
• memberaction_dropdown
• tag_fetchbit
• tag_fetchbit_complete
• forumrules
• navbits
• navbits_complete