Question

If you take a look at the code below you can see that I am running an if statement to check whether or not a text field is empty, if it is empty it runs the while loop. My question is when I am comparing the the two Variables, Q and Qc I only want to test the loop to a certain decimal place for example the tenths place.

I tried using @”%.1f” along with the variable but I am guessing my syntax is wrong. If someone could help me I would appreciate it.

        if ([heightTextField.text isEqualToString:@""]) {
            while (Q != Qc) {
                Hc = Hc + 0.01;
                Qc = 1.486*(Hc*W)*(powf(((Hc*W)/(2*Hc+2*W)), 0.6666666667))*(powf(S, 0.50))/n;
                H = Hc;
            }
        }
        if ([widthTextField.text isEqualToString:@""]) {
            while (Q != Qc) {
                Wc = Wc + 0.01;
                Qc = 1.486*(H*Wc)*(powf(((H*Wc)/(2*H+2*Wc)), 0.6666666667))*(powf(S, 0.50))/n;
                W = Wc;
            }
        }

Thanks,
Dana

Answer 1

There may be an easier way to go about this, but off hand, this would be the approach I would take.

First off, and this may not apply to you, but I’ve had issues comparing a textField to @”” (where it would never say this is true), so I had since used if ([myTextField.text length]) instead.

As for the comparison, this is the code I would use:

NSString *qString = [NSString stringWithFormat:@"%.1f", Q];
NSString *qcString = [NSString stringWithFormat:@"%.1f", Qc];
while (![qString isEqualToString:qcString]) {
    // continue code to update Qc...;
    // update qcString;
    qcString = [NSString stringWithFormat:@"%.1f", Qc];
}