How to reverse a string using only one variable

Question

How to reverse string using next conditions:

1) if string isn't parameter of function,

2) if string is place in global scope,

3) use loop like for, while,

4) can add one variable

Note: Can't use method .join, .split, .reverse and so on...
If it possible and not so hard for you make explain your solution, very grateful !

In other words, this is what you got:

 let s = 'any string';
 let p; // feel free to use at your discretion

 // your code here. No further variables, no functions and no built-ins
 // should console.log the reversed string

I'm understand that my solution is very close to my desire (conditions), but i can't generate other solution.

function convers(s){ //parameter 
	var str = "";//empty string for new converted string
	for(var i = s.length-1; i >= 0; i--)//loop decremebtation that count from end of string
	str+=s[i];//store result and assignments to str
	return str;// declare result 
}
console.log(convers("abcdef"));

I looked this source: javascript reverse string algorithm

Is there a faster Reverse String Algorithm for JavaScript? - but it is useless for me, sorry.

I'm sorry if my explanation is not clear enough. Sorry for my English, I'm beginner here :))))

but i can't generate other solution. What does this mean? Which part isn't working? — gurvinder372
– gurvinder372, Commented Apr 5, 2018 at 12:49
This smells of do my homework because I do not know what to do. — epascarello
– epascarello, Commented Apr 5, 2018 at 12:58
This looks like a surprisingly good homework/interview question because of conditions 1 (which sorts out recursions) and especially 4 — georg
– georg, Commented Apr 5, 2018 at 13:07

Nina Scholz · Accepted Answer · 2018-04-05 13:15:38Z

3

You could use a new variable for the reverted string and use the length property for iterating.

var string = 'abcdef',
    reverse = '';

while (reverse.length !== string.length) {
    reverse += string[string.length - 1 - reverse.length];
}
string = reverse;

console.log(string);

A bit shorter.

var string = 'abcdef',
    reverse = '';

while (reverse.length !== string.length) {
    reverse = string[reverse.length] + reverse;
}
string = reverse;

console.log(string);

edited Apr 5, 2018 at 13:15

answered Apr 5, 2018 at 13:10

Nina Scholz

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Comments

Darshan Dave · Accepted Answer · 2018-04-06 04:19:54Z

0

Please check below condition I hope it will help you

1) if string isn't parameter of function

function convers(s){ //parameter 
s = s.toString();
	var str = "";//empty string for new converted string
	for(var i = s.length-1; i >= 0; i--)//loop decremebtation that count from end of string
	str+=s[i];//store result and assignments to str
	return str;// declare result 
}
console.log(convers(132));

2) if string is place in global scope

function convers(){ //parameter 

	var str = "";//empty string for new converted string
	for(var i = dd.length-1; i >= 0; i--)//loop decremebtation that count from end of string
	str+=dd[i];//store result and assignments to str
	return str;// declare result 
}
var dd ="123";
console.log(convers());

3) can add one variable

function convers(s,dd){ //parameter 
	var str = "";//empty string for new converted string
	for(var i = s.length-1; i >= 0; i--)//loop decremebtation that count from end of string
	str+=s[i];//store result and assignments to str
	return str +dd;// declare result 
}
    function CallConvers(){
    var dd = "ADD";
    console.log(convers("abcdef",dd));
    }
    CallConvers();

edited Apr 6, 2018 at 4:19

answered Apr 5, 2018 at 13:03

Darshan Dave

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4 Comments

georg Over a year ago

3) can add one variable - you've got two (str and i)

Darshan Dave Over a year ago

please check now

Maxim Gordiyenko Over a year ago

Good third solutions, but if possible to declare just one variable it can be either global or local scope. Really I don't understand this solution, I deleted second parameter and nothing changed.

Darshan Dave Over a year ago

@MaximGordiyenko Please check 3rd solution

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