For Loop Does Not Work - objective-c

Question

I am trying to make a guessing app for school.
-(IBAction)check:(id)sender
{
if (answerField.text.length > 0)
{
[self number];
}
else
{
UIAlertView *error = [[UIAlertView alloc]
initWithTitle:#"Error"
message:#"Please type in more than one chracter"
delegate:self
cancelButtonTitle:#"Okay!"
otherButtonTitles:nil];
[error show];
}
}
-(void)number
{
for (int i = 0; i < 100; i++)
{
if (answerField.text > strNumber)
{
hlLabel.text = #"Guess Lower";
answerField.text = #"";
}
if (answerField.text < strNumber)
{
hlLabel.text = #"Guess Higher";
answerField.text = #"";
}
}
}
The Problem: The for loop does not work. It only checks once. Also, everytime it checks, it always says "Guess Higher" when in fact, I guess higher than the computer generate number.
Other Information: I have a method where every time I click the keyboard done from the textfield, it will check the number method.

Answer 1

answerField.text is returning an NSString, not a number.
Try answerField.text.intValue.
And strNumber must be an integer for that to work, btw.

Answer 2

It took me some time to understand what you were trying to do. But I suspect that you are just trying to have a user enter some number in a field to guess a number with up to 100 attempts. Something like that.
But a for loop is not how you can make a user retry something. What you need is some state saved in the object (i.e. an ivar) which counts each attempt.
Second problem here is that it seems you are numerically comparing strings which does not make sense here. You want to compare numerical values.
So your program would likely look like:
-(IBAction)check:(id)sender
{
if (answerField.text.length > 0)
{
[self checkFieldValueAgainstCorrectAnswer]; // use better naming
}
else
{
UIAlertView *error = [[UIAlertView alloc]
initWithTitle:#"Error"
message:#"Please type in more than one chracter"
delegate:self
cancelButtonTitle:#"Okay!"
otherButtonTitles:nil];
[error show];
}
}
-(void)checkFieldValueAgainstCorrectAnswer
{
NSUInteger fieldValue = [answerField.text unsignedIntegerValue];
NSUInteger correctValue = [strNumber unsignedIntegerValue];
if (fieldValue > correctValue) {
// guess lower
} else if(fieldValue < correctValue) {
// guess higher
} else {
// you won!
return;
}
answerField.text = #"";
attempts++;
if (attempts > 100) {
// Too many attemps, you lost!
}
}