# For loop minus number problem

• Newbie
• Posts: 8
• Loc: London

3+ Months Ago

Hi, the function minusNumber of my code is not working and I don't know why Any help much appreciated! thanks.
Code: [ Select ]
<html>

<script language="javascript">

function plusNumbers()
{
for (i = 0; i <= 10; i++)
{
alert("The number is +" + i)

}
}

function minusNumbers()
{
for (i = -0; i <= -10; i--)
{
alert("The number is -" - i)

}
}
</script>

<body>

<form>

Press PLUS to display 0 to +10: <input type="button" value="PLUS" onclick="plusNumbers()" ><br/>
Press MINUS to display 0 to -10: <input type="button" value="MINUS" onclick="minusNumbers ()">
</form>
</body>

</html>

1. <html>
3.
4.     <script language="javascript">
5.
6. function plusNumbers()
7. {
8.    for (i = 0; i <= 10; i++)
9.     {
10. alert("The number is +" + i)
11.
12.     }
13. }
14.
15.
16. function minusNumbers()
17. {
18.    for (i = -0; i <= -10; i--)
19.     {
20. alert("The number is -" - i)
21.
22.     }
23. }
24. </script>
25.
27. <body>
28.
29.
30. <form>
31.
32. Press PLUS to display 0 to +10: <input type="button" value="PLUS" onclick="plusNumbers()" ><br/>
33. Press MINUS to display 0 to -10: <input type="button" value="MINUS" onclick="minusNumbers ()">
34. </form>
35. </body>
36.
37.
38. </html>
39.
• Brewmaster
• Posts: 6302
• Loc: Seattle, WA

3+ Months Ago

Well, first of all, there's no such thing as negative zero.

Second, your loop condition is starting the loop at 0, but telling it to only execute while i is less than or equal to -10. What you really want is for the loop to execute while i is greater than or equal to -10.

Code: [ Select ]
for( i = 0, i >= -10; --i ) {
• Newbie
• Posts: 8
• Loc: London

3+ Months Ago

spork wrote:
Well, first of all, there's no such thing as negative zero.

Second, your loop condition is starting the loop at 0, but telling it to only execute while i is less than or equal to -10. What you really want is for the loop to execute while i is greater than or equal to -10.

Code: [ Select ]
for( i = 0, i >= -10; --i ) {

I put that code in and it is still not coming up with anything, pehaps because of
Code: [ Select ]
alert("The number is -" - i)
• Brewmaster
• Posts: 6302
• Loc: Seattle, WA

3+ Months Ago

Change that to
Code: [ Select ]
alert("The number is " + i);
• Newbie
• Posts: 8
• Loc: London

3+ Months Ago

I'm sorry, I don't know what's going on, I'm now getting no alert boxes. My code at the moment is
Code: [ Select ]
<html>

<script language="javascript">

function plusNumbers()
{
for (i = 0; i <= 10; i++)
{
alert("The number is +" + i);

}
}

function minusNumbers()
{
for( i = 0, i >= -10; --i )
{
alert("The number is " + i);

}
}
</script>

<body>

<form>

Press PLUS to display 0 to +10: <input type="button" value="PLUS" onclick="plusNumbers()" ><br/>
Press MINUS to display 0 to -10: <input type="button" value="MINUS" onclick="minusNumbers ()">
</form>
</body>

</html>
1. <html>
3.     <script language="javascript">
4. function plusNumbers()
5. {
6. for (i = 0; i <= 10; i++)
7.     {
8. alert("The number is +" + i);
9.     }
10. }
11. function minusNumbers()
12. {
13. for( i = 0, i >= -10; --i )
14.     {
15. alert("The number is " + i);
16.     }
17. }
18. </script>
20. <body>
21. <form>
22. Press PLUS to display 0 to +10: <input type="button" value="PLUS" onclick="plusNumbers()" ><br/>
23. Press MINUS to display 0 to -10: <input type="button" value="MINUS" onclick="minusNumbers ()">
24. </form>
25. </body>
26. </html>
• Proficient
• Posts: 284

3+ Months Ago

Do:

Code: [ Select ]
<html>
<script type="text/javascript">
{
var plusButton = document.getElementById('plusButton');
var minusButton = document.getElementById('minusButton');

plusButton.onclick = function()
{
for(var i = 0; i <= 10; i++)
{
alert("The number is: " + i);
}
}

minusButton.onclick = function()
{
for(var i = 0; i >= -10; i--)
{
alert("The number is: " + i);
}
}
}
</script>

<body>
Press to display the numbers 0 - 10: <button id="plusButton">Click!</button>
<br /><br />
Press to display the numbers 0 - -10: <button id="minusButton">Click!</button>
</body>

</html>
1. <html>
3.    <script type="text/javascript">
5.       {
6.          var plusButton = document.getElementById('plusButton');
7.          var minusButton = document.getElementById('minusButton');
8.
9.          plusButton.onclick = function()
10.          {
11.             for(var i = 0; i <= 10; i++)
12.             {
13.                alert("The number is: " + i);
14.             }
15.          }
16.
17.          minusButton.onclick = function()
18.          {
19.             for(var i = 0; i >= -10; i--)
20.             {
21.                alert("The number is: " + i);
22.             }
23.          }
24.       }
25.    </script>
27.
28. <body>
29.    Press to display the numbers 0 - 10: <button id="plusButton">Click!</button>
30.    <br /><br />
31.    Press to display the numbers 0 - -10: <button id="minusButton">Click!</button>
32. </body>
33.
34. </html>
• Newbie
• Posts: 8
• Loc: London

3+ Months Ago

Nightslyr wrote:
Do:

Code: [ Select ]
<html>
<script type="text/javascript">
{
var plusButton = document.getElementById('plusButton');
var minusButton = document.getElementById('minusButton');

plusButton.onclick = function()
{
for(var i = 0; i <= 10; i++)
{
alert("The number is: " + i);
}
}

minusButton.onclick = function()
{
for(var i = 0; i >= -10; i--)
{
alert("The number is: " + i);
}
}
}
</script>

<body>
Press to display the numbers 0 - 10: <button id="plusButton">Click!</button>
<br /><br />
Press to display the numbers 0 - -10: <button id="minusButton">Click!</button>
</body>

</html>
1. <html>
3.    <script type="text/javascript">
5.       {
6.          var plusButton = document.getElementById('plusButton');
7.          var minusButton = document.getElementById('minusButton');
8.
9.          plusButton.onclick = function()
10.          {
11.             for(var i = 0; i <= 10; i++)
12.             {
13.                alert("The number is: " + i);
14.             }
15.          }
16.
17.          minusButton.onclick = function()
18.          {
19.             for(var i = 0; i >= -10; i--)
20.             {
21.                alert("The number is: " + i);
22.             }
23.          }
24.       }
25.    </script>
27.
28. <body>
29.    Press to display the numbers 0 - 10: <button id="plusButton">Click!</button>
30.    <br /><br />
31.    Press to display the numbers 0 - -10: <button id="minusButton">Click!</button>
32. </body>
33.
34. </html>

Thank you! It works.

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