for loop parameter not working properly in JavaScript

Question

Hello: I'm new programming. My problem is that the evaluation in the for sentence is not working properly.

With: salir='n' it works correctly
With: salir=='n' don't works.

Thanks

<script type="text/javascript">
    var tabla="";
    var numusuario=0;
    var min=0;
    var max=9;
    var salir='s';
    numusuario=prompt("Escribe un número entre 0 y 9: ");
    for(var j=1;salir='n';j++) 
    {
        if(numusuario<0 || numusuario>=10)
        {
            salir='s';
            numusuario=prompt("Escribe un número entre 0 y 9: ");
        }
        else
        {
            for(var x=min;x<=max;x++)
            {
                tabla = tabla + x + " x " + numusuario + " = " + (x*numusuario) + "\n";
            }
            alert(tabla);
            break;
        }
    }
</script>

you should make deeper research with for loop

canbax
– canbax

2020-03-06 11:10:26 +00:00
Commented Mar 6, 2020 at 11:10 — canbax
– canbax, Commented Mar 6, 2020 at 11:10

kelvin kantaria · Accepted Answer · 2020-03-06 11:09:25Z

2

salir='n' means assignments. it is always return true

salir=='n' means comparision. it is return false because salir='s' so s is not equal to n

answered Mar 6, 2020 at 11:09

kelvin kantaria

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Comments

Jaime Blázquez · Accepted Answer · 2020-03-06 11:26:01Z

Several things happenning here, but main is that you are mixing different forms of flow control:

You are using salir (exit, for non-spanish speakers) as a loop end indicator, but...
The loop condition is always true (as salir='n' evaluates to 'n', which is true)
You are using also a variable, j, with no use (you do nothing with it, it doesn't participate in the loop condition neither)
The only posibility of exiting the loop is the break sentence, which exists the loop.

As the expected behaviour is not clear to me, I cannot assume a solution, but if it is to keep running until the user writes a valid number, then write the multiplication table of that number, it could be:

<script type="text/javascript">
    var tabla="";
    var numusuario=0;
    var min=0;
    var max=9;
    var salir = 'n';

    do {
        numusuario=prompt("Escribe un número entre 0 y 9: ");
        if(numusuario>0 && numusuario<10) {
            for(var x=min;x<=max;x++)
            {
                tabla = tabla + x + " x " + numusuario + " = " + (x*numusuario) + "\n";
            }
            alert(tabla);
            salir = 's';
        }
    } while(salir == 'n')


</script>

The do {} while () executes at least once and checks the condition at the end, that seems better suited in this case, we drop the j variable and use the salir variable as flow control until the user writes the correct number.

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