Help, can't call another class's method

Tried many ways based on other questions asked here but could not get a method call to another class to compile.

I'm writing a dedicated class to process arithmetic, for example class Arithmetic. It has no class variables. It subclasses no class (though I tried NSObject with failure). It will have methods of the type:

+ (NSString *)calculateEnergy:(NSString *)weight;

that I want to call from another class, in a static-method way, like:

self.label.text=[arithmetic calculateEnergy:@"8.0"];

where 'Arithmetic *arithmetic' is declared and given a retain property (synthe开发者_StackOverflow社区sised etc.) in the header and implementation of the class wanting to access the calculateEnergy method.

I've tried various suggestions, such as variations on:

[(Arithmetic *) arithmetic calculateEnergy:@"8.0"];

every time getting an "Accessing unknown 'calculateEnergy' getter method"

Thank you so much in advance!

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Though I don't have the complete picture, your method definition is for a class-level, static method, as opposed to an instance method. You would want to call it as

self.label.text = [Arithmetic calculateEnergy:@"8.0"];

You also would not need to create an instance of Arithmetic to call the method you have there.

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Is arithmetic not an instance of Arithmetic? If instead you try self.label.text=[Arithmetic calculateEnergy:@"8.0"]; you should be OK.