IOS9开发指南之Objective-C接口声明实现与调用_object c 怎么实现接口

1.接口声明

 
@interface Calculator: NSObject
{
    double accumulator;
}
 
-(void)   setAccumulator: (double) value;
-(void)   clear;
-(double) accumulator;
-(void) add: (double) value;
-(void) subtract: (double) value;
-(void) multiply: (double) value;
-(void) divide: (double) value;
 
@end

2.接口实现

@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

3.接口调用

Calculator *deskCalc;
        deskCalc =