CODEWITHSUNDEEP
javascript
aarocard
aarocard

Reputation: 17

I keep getting stuck in an infinite loop when testing a string using a function in a for loop

When I test a string using the inputName function, I get stuck in an infinite loop that keeps displaying the alert() functions in the browser. I'm not sure the logic behind why it's happening. Note this is for a school assignment and I'm required to use a for loop and a function with parameters to test inputted data called employeeName. The function tests to see if the data is null, empty or a number before returning a value.

<html>
<head>
<script type="text/javascript">
function inputName(name) 
{
    var flag;

    do
    {

        flag = false;
        if (name == null)
        {
            alert("You have hit the 'Cancel' button!");
            return name;
            flag = false;
        }
        if (name == "")
        {
            alert("You tried entering no name!");
            flag = true;
        }
        else if (!isNaN(name))
        {
            alert("You tried entering a number!");
            flag = true;
        }
        else if (name.length < 2)
        {
            alert("You tried entering a name less than 2 characters!");
            flag = true;
        }
    } while (flag);
    return name;
}
</script>
</head>
<body>
<script type="text/javascript">

// DECLARATIONS
var numEmployees;
var employeeName;
var testName;


// INPUT
numEmployees = prompt("Enter the number of employees");

// PROCESSING
for (var index = 1; index <= numEmployees; index++)
{
    employeeName = prompt("Enter a name.");
    testName = inputName(employeeName);
}

// OUTPUT

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

Upvotes: 0

Views: 333

Answers (3)

Dustin Kingen
Dustin Kingen

Reputation: 21275

You need to prompt the user to correct the name.

var getName = function() {
    var name;

    do {
        name = prompt("Enter a name.");
    } while(!validateName(name));

    return name;
};

var validateName = function(name) {
    if (name == null) {
        alert("You have hit the 'Cancel' button!");
        return true;
    }

    if (name == "") {
        alert("You tried entering no name!");
        return false;
    }
    else if (!isNaN(name)) {
        alert("You tried entering a number!");
        return false;
    }
    else if (name.length < 2) {
        alert("You tried entering a name less than 2 characters!");
        return false;
    }

    return true;
};

Upvotes: 0

epascarello
epascarello

Reputation: 207557

Because you are not prompting for a new name inside of the loop, the name never changes so you keep testing the same string over and over again.

Upvotes: 2

Pointy
Pointy

Reputation: 414006

You're not using a for loop; that's a do ... while loop.

The problem is that you set "flag" to true, but nothing happens to set it to false before you loop around and set it to true again. If the function starts off with the "name" being empty, a number, or a single-character string, that loop will just go on and on.

Upvotes: 1

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