Save value of the variable - ios7

Question

Here is the NSUserdefaults code.
-(IBAction)SaveButton:(id)sender {
NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];
NSString* Assignment0Text = screen0.text;
[defaults setObject:Assignment0Text forKey:#"Assignment0Text"];
[defaults synchronize];
}
-(IBAction)LoadButton:(id)sender {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString* temp0 = [defaults objectForKey:#"Assignment0Text"];
screen0.text = temp0;
}
This code above means that the program only saves and loads the string value inside the textfield/label.
My question is, how can I modify this code so that the NSUserDefaults can save and load the value of a variable (in this case int & float), not the text inside the textfield/label? So that when I load the program, all the integer/float values are the same. Not what's written in the text inside the textfield/label are the same. All that the screen is showing is a float number with variable called runningtotal.
screen0.text = [NSString stringWithFormat:#"%2.2f", runningtotal];

Answer 1

if I understand your question correctly, you should use wrappers for variables like int:
int value = 5;
[defaults setObject:#(value) forKey:#"Assignment0Number"];
the magic is the NSUserDefaults can not store non-object values like 5. You need to create NSObject object, store the value within it, and then save this object into the NSUserdefaults. That is what happens when I write '#(value)'.
If to be more precise, #(value) is literal for [NSNumber numberWithInt:value], and since NSNumber is the object and subclass of NSObject, the value can be stored now.
EDIT:
here is what you probably want (I assume that runningtotal is the class variable):
-(IBAction)SaveButton:(id)sender {
NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];
[defaults setObject:#(runningtotal) forKey:#"Assignment0Text"];
[defaults synchronize];
}
-(IBAction)LoadButton:(id)sender {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSNumber* temp0 = [defaults objectForKey:#"Assignment0Text"];
runningtotal = [temp0 intValue];
}