output for a texteild is zero rather then an actual result - ios

Question

This is a strange output, I seem to trigger the alert view each time, and the value for num1 would be 0.50 which is fine.
When I click calculate the alert field is triggered, and what's more num1 is set to 0.00, and the tcost which is the total cost seems to always be 0.
This has never happened before.
The type out of output should be something such as a 0.23 etc.. for tcost the reason for the alert field is so i can trap if a user has not filled a field out.
(void)textFieldDidEndEditing:(UITextField *)textField
{
CGRect viewFrame = self.view.frame;
viewFrame.origin.y += animatedDistance;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
[self.view setFrame:viewFrame];
[UIView commitAnimations];
if (textField1) {
NSString *txt = self.textField1.text;
double num1 = [txt doubleValue];
double tCost = num1/100;
NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
[numberFormatter setMaximumFractionDigits:3];
[numberFormatter setRoundingMode: NSNumberFormatterRoundUp];
NSString *numberString = [numberFormatter stringFromNumber:[NSNumber numberWithFloat:tCost]];
self.textField1.text = [NSString stringWithFormat:#"%#",numberString];
}
}
(IBAction)calculateCost:(UIButton *)sender {
NSString *rate = self.textField1.text;
NSString *wat = self.textField2.text;
NSString *hours = self.textField3.text;
NSString *Days = self.textField4.text;
long double num1 = [rate doubleValue];
long double num2 = [wat doubleValue];
long double num3 = [hours doubleValue];
long double num4 = [Days doubleValue];
//double num12 = num1 /10000;
double appKw = num2 / 1000;
double costKwph = appKw *num1;
double tCost = ((num4 * num3) * costKwph);
if (num2 == 0|| num1 <= 0.000|| num3 == 0 || num4 == 0) {
self.textField5.text = 0;
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"oops" message:#"you must fill in all fields" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"OK",nil];
[alert show];
}
tCost = tCost / 100;
NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
[numberFormatter setMaximumFractionDigits:4];
NSString *numberAsString = [numberFormatter stringFromNumber:[NSNumber numberWithFloat:tCost]];
self.textField5.text = [NSString stringWithFormat:#"%#",numberAsString];
}

Answer 1

Try to convert your textField in NSNumber, for example:
NSNumberFormatter * f = [[NSNumberFormatter alloc] init];
[f setNumberStyle:NSNumberFormatterDecimalStyle];
NSNumber * num1 = [f numberFromString:self.textField1.text];

Answer 2

if (textField == self.textField1) {
NSNumberFormatter *nFormatter = [[NSNumberFormatter alloc] init];
[nFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
self.textField1.text = [nFormatter stringFromNumber:[NSNumber numberWithFloat: [self.textField1.text doubleValue] / 100]];
}
You can not extract float from currency, hence why the result in textField5 is zero. so forma the above to output to a corresponding label so the user can see the formatted string like so.
if (textField == self.textField1) {
NSNumberFormatter *nFormatter = [[NSNumberFormatter alloc] init];
[nFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
self.labeltest.text = [nFormatter stringFromNumber:[NSNumber numberWithFloat: [self.textField1.text doubleValue] /100]];