Question

Hi I have the following class called CalculatorOperations:

#import "CalculatorOperations.h"

@implementation CalculatorOperations

+(float)add:(float)numOne with:(float)numTwo{
    return numOne + numTwo;
}
@end

I then try to call this class method as follows from within my Calculator class:

#import "Calculator.h"
#import "CalculatorOperations.h"
#import <Foundation/Foundation.h> 

@implementation Calculator

+(float)add:(float)numOne to:(float)numTwo{
    CalculatorOperations *calcOp = [CalculatorOperations alloc];
    float answer = [calcOp add:numOne with:numTwo];
    return answer;
}

@end

The problem is I keep getting a “incompatible types in initialisation” message when trying to assign the return value of a the add:with method to a variable (answer).

Why is this?

Answer 1

You shouldn’t be calling a class method (the + indicates class method) on an instance of the class. In addition, you aren’t initing the class as required for an instance of that class.

Try this:

@implementation Calculator

+(float)add:(float)numOne to:(float)numTwo{
    return [CalculatorOperations add:numOne with:numTwo];
}

@end