使用Object-c类实现简单地加减乘除运算

//
//  main.m
//  prog1
//
//  Created by songjs on 15-1-6.
//  Copyright (c) 2015年 songjs. All rights reserved.
//

#import <Foundation/Foundation.h>
//实现一个简单的4则运算计数器

@interface Calculator:NSObject
//累加方法
-(void) setAccumulator:(double) value;
-(void) clear;
-(double) accumulator;

//算术方法
-(void) add:(double) value;
-(void) subtract: (double) value;
-(void) multiply:(double) value;
-(void) divide:(double) value;
@end

@implementation Calculator{
double accumulator;
}
-(void) setAccumulator:(double)value{
accumulator = value;
}
-(void) clear{
accumulator = 0;
}
-(double) accumulator{
return accumulator;
}

//算术方法实现
-(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, const char * argv[]) {
@autoreleasepool {
//使用
Calculator *deskCalc = [[Calculator alloc] init];

[deskCalc setAccumulator:100.0];
[deskCalc add:200.0];
[deskCalc divide:15.0];
[deskCalc subtract:10.0];
[deskCalc multiply:5];

NSLog(@"the result is %g\n",[deskCalc accumulator]);
}
return 0;
}