How to modify and revert a simple Java Script loop

Question

I'm learning basics of Java Script. I want to print the following in the console:

*2345
**345
***45
****5
*****
*****
****5
***45
**345
*2345

I've already wrote the code: var x = 5; var line;

for(var i = 0; i<x; i=i+1){
    line = "";
    for(var j=0; j<x; j=j+1){
        if(j <= i){
            line = line + " * ";
        }
    }
    console.log(line);
}
for(var i = x; i>0; i--){
    line = "";
    for(var j=0; j<x; j=j+1){
        if(j <= i-1){
            line = line + " * ";
        }
    }
    console.log(line)
}

So the result is:

*
**
***
****
*****
*****
****
***
**
*

Could anybody help me to modify the loop? I've tried various things but it never works.

Looks like an assignment question!

Katti
– Katti

2015-10-11 11:03:16 +00:00
Commented Oct 11, 2015 at 11:03 — Katti
– Katti, Commented Oct 11, 2015 at 11:03
What conditions does your assignment set? :)

turbopipp
– turbopipp

2015-10-11 11:14:02 +00:00
Commented Oct 11, 2015 at 11:14 — turbopipp
– turbopipp, Commented Oct 11, 2015 at 11:14

Katti · Accepted Answer · 2015-10-11 11:10:37Z

2

You can use this for both the if conditions :

else {
line += j + 1;
}

answered Oct 11, 2015 at 11:10

Katti

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Comments

guramidev · Accepted Answer · 2015-10-11 11:14:03Z

I would have done it like this:

    var numbers = [1,2,3,4,5],
    nLength = numbers.length,
    result = [],
    stringOf = function( value,times,str ) {

      if( 'undefined' === typeof str )
        str = '';

      if( times === 0 )
        return str;

      str += value;

      times--;

      return stringOf( value,times,str );

    },
    log = function( el ) { console.log( el ) };

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

  result[ i ] = stringOf( '*',i + 1 ) + numbers.slice( i + 1,nLength).join('');
  result[ i + nLength ] = stringOf( '*',nLength - i ) + numbers.slice( nLength - i,nLength).join('');

}

result.map( log );

Output:

*2345
**345
***45
****5
*****
*****
****5
***45
**345
*2345

Editing numbers array would change the output which will be in the same manner as specified.

Quentin Roy · Accepted Answer · 2019-04-23 09:40:30Z

1

var baseString = "12345";
var starStrings = [];

for(var i = 0; i < baseString.length; i++){
  starStrings.push("*".repeat(i + 1) + baseString.slice(i + 1));
}
starStrings = starStrings.concat(starStrings.slice().reverse());

starStrings.forEach(function(s){
  document.write(s + "<br />");  
});

edited Apr 23, 2019 at 9:40

answered Oct 11, 2015 at 11:09

Quentin Roy

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