calculating problem

[linepisode]

hi all,

i am trying to calculate like this:

float *myResult;
	int myVal=[txt.text floatValue];
        myResult = myVal / 60;

        label1.text = myResult;

it doesnt calculate and doesnt quit the application when i enter 0 - 59 to textfield. but when i enter minimum 60, application closing. where is the problem?

[Domele]

myVal is an int. doing [.... floatValue] will return a float. You are assigning myVal by doing myVal = [... floatValue]. Can you connect the dots?

[linepisode]

Originally Posted by Domele

myVal is an int. doing [.... floatValue] will return a float. You are assigning myVal by doing myVal = [... floatValue]. Can you connect the dots?

ok forget this code. I just tried to find right code. Can you get the point what i try to do? I want to make division textfield's value and "60".

[Domele]

Your code is almost right. You just need to change one part. You want to assign an int to your variable myVal. You need to get an integer value from your text field. If [...floatValue] returns a float, what do you think the method for getting an int is? If you really don't know or you are really lazy, google it.

[linepisode]

Originally Posted by Domele

Your code is almost right. You just need to change one part. You want to assign an int to your variable myVal. You need to get an integer value from your text field. If [...floatValue] returns a float, what do you think the method for getting an int is? If you really don't know or you are really lazy, google it.

i changed my code like this:

float *myResult;
	int myVal=txt.text;
        myResult = myVal / 60;

        label1.text = myResult;

But same problem again. Application halts when i enter bigger value than 60.

[Domele]

I'm going to put it out there, your code should crash the second it runs. You are trying to assign an int with an NSString. And then you are trying to assign an NSString value with a float. I'm going to try some correct code really quickly to see if it does crash, but I doubt it. Anyways it seems that you are just copying and pasting code from somewhere. Please understand the code before you put it in your project.

Edit: Yep, just tried it. If you do it right it shouldn't crash. If you pay me I'll give you the code but otherwise you need to come up with your own. I can help you but I can't give it to you.

[Duncan C]

Originally Posted by linepisode

i changed my code like this:

float *myResult;
	int myVal=txt.text;
        myResult = myVal / 60;

        label1.text = myResult;

But same problem again. Application halts when i enter bigger value than 60.

	int myVal=txt.text;

This line is wrong. You can't take a string and assign it to an integer.

You had it almost right the first time, with the line

	float myVal=[txt.text floatValue];

(Except that it should be "float myvalue" not "int myValue")
Now, once you calculate your new value, you want to assign it back to your label. The label.text property is a string. So, you need to convert your result, which is a float, to a string. You can't just set a string to a floating point number. It will give you a compiler warning, and may crash, depending on the value you assign.

So this line:

        label1.text = myResult;

is VERY wrong. Crash your program wrong.

You need to convert your floating point value to a string.

Take a look at the method stringWithFormat. It lets you build a string out of different parts, and do format conversion while you're at it.

the expression
[NSString stringWithFormat: @"%f", 30.0]

will convert the floating point number 30 to a string, @"30". See if you can adapt that to solve your problem.

[linepisode]

Originally Posted by Duncan C

	int myVal=txt.text;

This line is wrong. You can't take a string and assign it to an integer.

You had it almost right the first time, with the line

	float myVal=[txt.text floatValue];

(Except that it should be "float myvalue" not "int myValue")
Now, once you calculate your new value, you want to assign it back to your label. The label.text property is a string. So, you need to convert your result, which is a float, to a string. You can't just set a string to a floating point number. It will give you a compiler warning, and may crash, depending on the value you assign.

So this line:

        label1.text = myResult;

is VERY wrong. Crash your program wrong.

You need to convert your floating point value to a string.

Take a look at the method stringWithFormat. It lets you build a string out of different parts, and do format conversion while you're at it.

the expression
[NSString stringWithFormat: @"%f", 30.0]

will convert the floating point number 30 to a string, @"30". See if you can adapt that to solve your problem.

Thank you Duncan C, i'll try it tomorrow morning. 4:35 AM here
Also thank you, Domele. BTW i'm not copy/paste programmer. I'm newbie and trying improve myself. Sometimes i can make wrong, but i'm learning new things when i do wrong.


Edit: Thank you again Duncan C, it works for me