Question

I’m trying to make an app to convert a decimal number into a binary number, but when I input the decimal number into a text field and have a button call the binaryConvert method, it continually returns 111111111111111111 (1 for every evaluation). Why is this??

- (NSString*)binaryConvert:(int)decNum {

    int i = 1;
    int value = 524288;
    NSString * binary = @".";

    while (i <= 19) {
        if ((decNum/value) >= 1) {
            binary = [binary stringByAppendingString:@"1"];
            decNum -= value;
        }   else {
            binary = [binary stringByAppendingString:@"0"];
        }
        value /= 2;
        i++;
    }
    return binary;
}

- (IBAction)convertToBinary:(id)sender {

    int decNum = (int)textField.text;
    if ([textField.text length] > 6) {
        answer.text = @"Too many numbers entered.";
    }   else {
        answer.text = [self binaryConvert:decNum];
    }
    [textField resignFirstResponder];
}

answer is a label.

Answer 1

int decNum = (int)textField.text; // WRONG

Should be:

int decNum = [textField.text intValue];

// my previous wrong answer:

// decNum -= value should be done everytime; not only on if ((decNum/value) >= 1)