CODEWITHSUNDEEP
javascript
user2296177
user2296177

Reputation: 2837

My function is not printing anything

The algorithm is supposed to sum two elements of the array and insert them between the two elements used in the sum.

Example input ==> output :

[1, 2, 3, 4] ==> [ 1, 3, 2, 5, 3, 7, 4]    


function growArray() {
    var sequence = [];
    sequence = window.prompt("Enter a number sequence", "1 2 3 4");
    for (var i = 0; i < sequence.length - 1; i += 2) {
        if (!((i + 1) in sequence)) {
            return;
        } // prevent out of bounds access
        var new_value = sequence[i] + sequence[i + 1];
        sequence.splice(i + 1, 0, new_value); // insert value at i + 1
    }

    for (var v in sequence) {
        document.write(v + ", ");
    }
}
<p>
    <input id="f1" type="button" value="Function 1" onclick="growArray();" />Click to expand array
</p>

Upvotes: 3

Views: 288

Answers (3)

JsingH
JsingH

Reputation: 189

here is what gets the output

function growArray() {
    var input = window.prompt("Enter a number sequence", "1 2 3 4");
    var sequence = input.split(" ");
    for (var i = 0; i < sequence.length - 1; i += 2) {
        if (i + 1 > sequence.length) {
            return;
        } // prevent out of bounds access
        var new_value = parseInt(sequence[i]) + parseInt(sequence[i + 1]);
        sequence.splice(i + 1, 0, new_value); // insert value at i + 1
    }
    document.write(sequence.toString());
}
<p>
    <input id="f1" type="button" value="Function 1" onclick="growArray();" />Click to expand array
</p>

Upvotes: 2

Panos Bariamis
Panos Bariamis

Reputation: 4653

You have to split user input into an array (sequence).

This array contains string values because user input is string. So you have to map those values in int, in order to add them. 

var sequence = '1 2 3 4'.split(' ').map(Number);
for(var i=0; i<sequence.length - 1; i+=2) {
    sequence.splice(i+1, 0, sequence[i] + sequence[i+1]);
}
document.write(sequence.join(', '));

working example

Upvotes: 0

Bonatti
Bonatti

Reputation: 2781

There are several points to look upon your code.

sequence is an array, but you did not defined a type, or even parsed the inputs. It is a String array as far as I can read.

Documentation states: The split() method splits a String object into an array of strings by separating the string into substrings.

Then, your array keeps getting altered while you work on it. While this is no error, it is "weird" for the task at hand, and the apparent dominium you have over the language.

example(){
   var original = [1, 2, 3, 4];
   var result=[];
   for(var i=0;i<original.length;i++){
      result.push(original[i]);
      if(i<original.length-1){
         result.push(original[i]+original[i+1]);
      }
   }
   alert(result);
}

Upvotes: 0

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