Creating a Calculator Class

Creating a calculator class in Objective C is not an easy task! Oh, c’mon sure it . I’ve been reading about operators lately. Arithmetic operators, bit operators, assignment operators etc. The fact that many of these things were known helps me gap the lack of time to proceed with reading as I wanted too. Here is my last code:

	#import <objc/Object.h>
	#import <stdio.h>

	@interface Calculator: Object
	{
		double accumulator;
	}

	// accumulator methods

	-(void) setAccumulator: (double) value;
	-(void) clear;
	-(double) accumulator;

	// arithmetic methods

	-(void) add: (double) value;
	-(void) subtract: (double) value;
	-(void) multiply: (double) value;
	-(void) divide: (double) value;

	@end

	@implementation Calculator;

	-(void) setAccumulator: (double) value
	{
		accumulator = value;
	}

	-(void) clear
	{
		accumulator = 0;
	}

	-(double) accumulator
	{
		return accumulator;
	}

	-(void) add: (double) value
	{
		accumulator += value;
	}

	-(void) subtract: (double) value
	{
		accumulator -= value;
	}

	-(void) multiply: (double) value
	{
		accumulator *= value;
	}

	-(void) divide: (double) value
	{
		accumulator /= value;
	}

	@end

	int main (int argc, char *argv[])
	{
		Calculator *calc;

		calc = [[Calculator alloc] init];

		[calc clear];
		[calc setAccumulator: 100.00];
		[calc add: 200.00];
		[calc divide: 15.00];
		[calc subtract: 10.00];
		[calc multiply: 5.00];

		printf(”The result is %g\n”, [calc accumulator]);
		[calc free];

		return 0;
	}
	

Okay, pretty simple you’ll say! But it’s not! Actually for the first time some things came natural! The allocation and initialisation of memory, I didn’t even think about the right syntax after the first line [calc clear]; which helped write the program quickly. However I made some mistakes the first I wrote the program. The first one was not paying attention that the accumulator was of type “double” and not “void” which caused some warning but not fatal errors