Problem when finishing program when typing word in javascript

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Problem when finishing program when typing word in javascript

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#1 by (1 votes)
#2 by (0 votes)

0

When I ask the question "Enter another name to check if it is found or not" when typing end, you must end the program, but it does not. What should I modify?

<!DOCTYPE html>
<html lang="es">
<head>
<meta charset="utf-8" />
<title>Ej 2</title>
</head> 
<body>

<script type="text/javascript">

var nombres=[];
var respuesta;


for (var i=1; i<=10; i++) { 
    nombres[i]=prompt("Introduce el nombre " +i);
}

var comprueba=prompt("Introduce otro nombre más para comprobar si se encuentra o no");

do {
var posicion=0;
for (var i=1; i<=10; i++) {
    if(comprueba==nombres[i]) {
        posicion=i;
     }
   }  

if(posicion!=0) {
alert("El nombre " +comprueba+ " ha sido encontrado en la posición " +posicion);
}else{
alert("El nombre " +comprueba+ " no ha sido encontrado");
}   


}while(respuesta=="fin")

</script>
</body>
</html>

javascript

asked by user09b 17.10.2018 в 13:02

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2 answers

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score 1 · Answer 1

I think there are several things to consider. As you have been told in the comments:

The do-while is not well done. You are running the code contained in the while respuesta == "fin" when you have to do the opposite, when the user enters "end" is when the do-while ends.

You have not defined the value of respuesta because you are not asking at any time so it will always be undefined .

If you want to repeat the loop do-while n times, you will also have to ask for the new word to search within that loop

Extra comments :

Get used to using let more often. var creates global variables which can give you problems of conflict between variables or unwanted behavior. More info here and here .

Get used to using the strict comparators (=== and! ==) that not only compare the value but also the type of object. More info here and here .

 <!DOCTYPE html>
    <html lang="es">
    <head>
    <meta charset="utf-8" />
    <title>Ej 2</title>
    </head> 
    <body>

    <script type="text/javascript">

    let nombres=[];    
	let respuesta;

    for (let i=1; i<=10; i++) { 
        nombres[i]=prompt("Introduce el nombre " +i);
    }

    do {
    let comprueba=prompt("Introduce otro nombre más para comprobar si se encuentra o no");
    
    let posicion=0;
    for (let i=1; i<=10; i++) {
        if(comprueba==nombres[i]) {
            posicion=i;
         }
       }  

    if(posicion!==0) {
    	alert("El nombre " +comprueba+ " ha sido encontrado en la posición " +posicion);
    }else{
    	alert("El nombre " +comprueba+ " no ha sido encontrado");
    }   

	respuesta = prompt("Si desea finalizar introduzca 'fin'");

    }while(respuesta.toLowerCase()!=="fin")

    </script>
    </body>
    </html>

You could do more things like compare the string entered is a text other than empty, for example, but I leave that to you;)

score 0 · Answer 2

There are three problems in your code:

1.- Just ask the user once a name to check if it exists in the list. Therefore, once it enters the do-while, an infinite loop occurs, since it NEVER changes that name.

2.- you have the variable comprueba to read what the user asks, but then the loop checks with respuesta that has NEVER changed in your code.

3.- your check in the loop is ==. This means that it will only be in the loop if what your user types is fin . In case of writing a name, you would not fulfill the condition and it would get out of the loop. The correct condition would be != . To solve 1, you can do:

do {
var comprueba=prompt("Introduce otro nombre más para comprobar si se encuentra o no");

That is, first the do, then the var checks.

to solve 2, instead of using respuesta in the condition of the loop, change it by comprueba :

}while(respuesta!="fin")

to solve 3, you must understand that do-while is hacer-mientras , that is, as long as respuesta IS NOT end, you want to repeat the loop. Therefore, the condition is with! =.