I am using a NSStepper along with a NSTextField. The user can either set the value using the text field or can use the NSStepper to change the value. I will quote my question using the example below:
Suppose the current value of my stepper is 4 and increment value of the stepper is 2:
After I click the UP arrow on the NSStepper the value becomes:
Now Suppose the current value would have been 4.5 i.e.:
After using the UP arrow the value becomes:
What I require is that when the current value is 4.5, after using the UP arrow, the value becomes 6 instead of 6.5
Any ideas to accomplish this are highly appreciated!
What I require is that when the current value is 4.5, after using the
UP arrow, the value becomes 6 instead of 6.5
Hard to tell exactly what you are asking but taking a guess: it sounds like you want to remove the decimal part of the number and increment by your defined step amount (2). You can do this through the floor() function. See here for other Objective-C math functions
double floor ( double ) - removes the decimal part of the argument
NSLog(#"res: %.f", floor(3.000000000001));
//result 3
NSLog(#"res:%.f", floor(3.9999999));
//result 3
If I understand what you want, this code will give you the next even number (up or down depending on which arrow you click), but still allow you to enter non-integer numbers in the text filed. tf and stepper are IBOutlets and num is a property (a float) that keeps track of the value of the stepper before you click an arrow so you can compare with the new number to see if the up or down arrow was clicked.
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
self.num = 0;
self.tf.intValue = 0; //the stepper is set to 0 in IB
}
-(IBAction)textFieldDidChange:(id)sender {
self.num = self.stepper.floatValue = [sender floatValue];
}
-(IBAction)stepperDidChange:(id)sender {
if (self.num < self.stepper.floatValue) { //determines whether the up or down arrow was clicked
self.num = self.stepper.intValue = self.tf.intValue = [self nextLargerEven:self.num];
}else{
self.num = self.stepper.intValue = self.tf.intValue =[self nextSmallerEven:self.num];
}
}
-(int)nextLargerEven:(float) previousValue {
if ((int)previousValue % 2 == 0) {
return (int)previousValue + 2;
}else
return (int)previousValue + 1;
}
-(int)nextSmallerEven:(float) previousValue {
if ((int)previousValue % 2 == 0) {
if ((int)previousValue == previousValue) {
return (int)previousValue - 2;
}else{
return (int)previousValue;
}
}else
return (int)previousValue - 1;
}
Related
For my app (OSX, not IOS) i have a geometric sequence (stored in container array) generated like this:
- (void)initContainerFor:(NSInteger)maxRows
{
self.container = [[NSMutableArray alloc] init];
NSInteger start = [self.firstTextFieldValue integerValue];
NSInteger ratio = [self.secondTextFieldValue integerValue];
// ASCENDING
for (NSInteger i = 1; i < (maxRows +1 ); i++)
{
NSInteger currentValue = start * pow(ratio,i-1);
[self.container addObject:currentValue];
}
}
User can enter the "start" and "ratio" integer. I want to give a feedback if limit (MAX_INT) is exceeded. I wrote this function:
- (BOOL)maxCheck
{
if ([self.container lastObject] > INT_MAX)
return false;
return true;
}
But this seems not to work. If i enter 2 for start and 200 for ratio i have this container content:
Container: (
2,
400,
80000,
16000000,
"-1094967296",
49872896,
1384644608,
2051014656,
"-2113929216",
0
)
Please help to understand what i see in the container (strings??) and how to get a correct check for the maximum value.
As you can see from log of array, you actually exceed INT_MAX limit twice, when next element become negative. So you can just add check to initContainer: method - if element is less then the previous, INT_MAX limit is reached.
TIP: INT_MAX is a signed value.
You can not compare the value after overflow with INT_MAX, as the overflow already happened. Or put differently, by its very definition and semantics, no integer can be bigger than INT_MAX.
What you can test is
[self.container lastObject] > INT_MAX/ratio
to find the sequence element that would cause overflow in the next step.
I am taking an introduction to Java programing class and I have an array list where I need to exclude the first element from my for loop that finds an average. The first element in the array list is a weight for the average (which is why it needs to be excluded). I also need to drop the lowest value from the remainder of the array list hence my second for loop. I have tried to create a copy of the list and also tried to create a sub list but I cannot get it to work.
public static double Avgerage(ArrayList<Double> inputValues) {
double avg;
double sum = 0;
double weightValue = inputValues.get(0);
double lowest = inputValues.get(0);
for (int i = 1; i > inputValues.size(); i++) {
if (inputValues.get(i) < lowest) {
lowest = inputValues.get(i);
}
}
for (int i = 0; i < inputValues.size(); i++) {
sum = sum + inputValues.get(i);
}
double average = (sum - lowest) / (inputValues.size() - 1);
avg = average * weightValue;
return avg;
}
To start with good programming practice, you should work with interfaces rather than classes, where possible. The appropriate interface here is List<Double>, and when you create it in your class, you should use
List<Double> nameOfList = new ArrayList<Double>();
What we're doing is creating an object which has the behaviour of a List, with the underlying implementation of an ArrayList (more info here.
With regards to the question, you don't appear to be excluding the first element, as you said you wished to - both for loops iterate through all values in the list. Remember to treat the ArrayList like an array - accessing an element does not modify it, like it might in a Queue.
I have edited your code below to demonstrate this, and have also included some other optimisations and corrected the sign error on line 7:
public static double average(List<Double> inputValues) {
double sum = 0;
//Exclude the first element, as it contains the weight
double lowest = inputValues.get(1);
for (int i = 2; i < inputValues.size(); i++) {
lowest = Math.min(inputValues.get(i), lowest);
}
for (int i = 1; i < inputValues.size(); i++) {
sum += inputValues.get(i);
}
double average = (sum - lowest) / (inputValues.size() - 1);
//Scale by the weight
avg *= inputValues.get(0);
return avg;
}
Note: The convention in java is to use camelCase for method names, I have adjusted accordingly.
Also, I don't know your requirements, but optimally, you should be providing logical parameters. If possible do the following before calling the function:
int weight = inputValues.get(0);
inputValues.remove(0);
//And then you would call like this, and update your method signature to match
average(inputValues, weight);
I don't do this inside the method, as the context implies that we would not be modifying values.
I need to toggle three different font sizes in the view controller for terms and conditions screen in an endless loop (13 , 15, 17..13, 15, 17..etc..). The screen is pretty simple, just text on full screen and a button in the navigation bar that when pressed, triggers and event handled in action.
The three fonts are represented by three NSString constants.
-(IBAction)toggleFontSize:(id)sender
{
if (self.currentFontIdentifier == regularFontIdentifier)
{
self.currentFontIdentifier = largeFontIdentifier;
}
else if (self.currentFontIdentifier == largeFontIdentifier)
{
self.currentFontIdentifier = smallFontIdentifier;
}
else
{
self.currentFontIdentifier = regularFontIdentifier;
}
self.termsAndConditionsTextView.font = [[BrandingManager sharedManager] fontWithIdentifier:self.currentFontIdentifier];
}
This code works (for now :)), but it's a nice Mediterranean IF yacht.I am wondering if there is some more mature approach. I already see the stakeholders changing their mind and adding a 4th font size. I want it to be manageable better, so basically once they add a new size I would only add it into some Array and that would be it.
Any ideas for a more mature algorithm?
Declare an instance variable for the current selected index and an array for the three fonts (small, regular and large) and try this:
-(IBAction)toggleFontSize:(id)sender {
_currentSelectedIndex = (_currentSelectedIndex + 1) % 3;
self.currentFontIdentifier = _fontIdentifiers[_currentSelectedIndex];
self.termsAndConditionsTextView.font = [[BrandingManager sharedManager] fontWithIdentifier:self.currentFontIdentifier];
}
You may not need currentFontIdentifier property since it can be obtained with _fontIdentifiers[_currentSelectedIndex]
You could use the methods 'indexOfObject and 'lastObject' of the NSArray class, something like:
Using an array of sizes:
NSArray *fontList = #[#"12","14","18"];
Then you could iterate through it using the indexOfObject
NSUInteger ix = [fontList indexOfObject:self.currentFontIdentifier] + 1;
if ([[fontList lastObject] isEqual:self.currentFontIdentifier])
ix=0;
self.currentFontIdentifier = [fontList objectAtIndex:ix];
or
NSUInteger ix = [fontList indexOfObject:self.currentFontIdentifier] + 1;
if (ix >= [fontList count])
ix=0;
self.currentFontIdentifier = [fontList objectAtIndex:ix];
I have a list of variables that are named based on two digits then a word i.e. val11 or val26
I need to perform a check on whether a certain value for a variable is equal to the next variable i.e. that val32 == val33
I have the names of the first variables that I need to check in an NSArray (i.e val33)
I can then write a function to perform the check as a lot of long winded if statements
-(void)checkValues:(NSArray *)valueArray {
for (int x = 0; x < [valueArray count]; x++) {
tempStr = [offFiles objectAtIndex:x];
//split variable name
NSString *value = [tempStr substringWithRange:NSMakeRange(3,2];
int numValue= [value intValue];
//long winded if statement
if (numValue == 11) {
if(val11 == val12) {
//do something
}
}
if (numValue == 12) {
if(val12 == val13) {
//do something
}
}
.... etc
if (numValue == 87) {
if(val87 == val88) {
//do something
}
}
}
}
Is there any way I can remove the long winded if statement and replace it with a reference to the next variable so that no matter what variable name is in the array I can easily just check it against the next variable
Something like the excel command indirect
=INDIRECT(CONCATENATE("Cell!A",numValue + 1))
Unless there is some need for you to store your data in a set of discrete separate variables, this is clearly a situation were an array would work for you. This could be either a c-style array or one using NSArray - its up to you.
Using a c-style array (assuming 10 completely made up values):
int myValues[10] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 }
Then your series of if statements can be reduced to one:
if (myValues[numValue] == myValues[numValue+1]) {
// so something
}
So if numValue is 3, it would compare myValues[3] and myValues[4] - essentially the same as comparing val3 and val4 in your scheme. Please note that arrays are zero based - the first value is accessed myValue[0] - so if your numbering scheme is 1-based then you need to subtract 1, e.g.:
if (myValues[numValue-1] == myValues[numValue]) {
// do something
}
Beside from the syntax bugs (like starting variable names with a number), what you are looking for is the switch() statement:
switch(a)
{
case 1: // if a is 1 do the following
printf("a is 1");
break;
case 2: // if a is 2
printf("a is 2");
break;
....
default: // if a was none of the cases before do this
printf("a sucks!!");
}
Notice that you always need a break; statement at the end of each case x:
I have been attempting to create an if else statement that will return a text string based on certain constraints. The first 3 constraints work, but when the event of the final constraint occurs, it triggers the second again. The random number generator occasionally used a 0 value, so I wanted to account for that. I am new to this, and apologize for indenting, etc.
I have been looking around here for a bit and couldn't find anything that seemed to cover this. If I missed it, a hint in the right direction would be appreciated as well.
double txtestimateCategory = [mynum computeVolume];
NSLog(#"The volume is %f", txtestimateCategory);
int v = ((txtestimateCategory * 1));
if ((v >= 8000))
{
NSLog(#"The box is large");
}
else if ((1 <= v < 1000))
{
NSLog(#"The box is small");
}
else if ((1000 <= v < 8000))
{
NSLog(#"The box is medium");
}
else
{
NSLog(#"The box is a lie");
}
Comparators are binary operators. You have to write:
else if (1 <= v && v < 1000)
etc.
(Otherwise you would be evaluating things like true < 1000, and true converts to 1 implicitly. Not what you meant!)