ios-A+B经典问题

//
//  main.m
//  a+b
//
#import <Foundation/Foundation.h>
#import "Calcultor.h"
int main(int argc, const char * argv[])
{

    Calcultor * cal = [[Calcultor alloc]init];
    
    [cal setA:10];
    [cal setB:20];
    
    int result = [cal add];
    NSLog(@"%d",result);
    
    NSLog(@"%d",[cal sub:10 andb1:10]);

    return 0;
}

//
//  Calcultor.h
//  a+b
//

#import <Foundation/Foundation.h>

@interface Calcultor : NSObject
{
    int _a;
    int _b;
}
/*set get */
@property int a;
@property int b;


-(int)add;

-(int)sub:(int)a1 andb1:(int)b1;

@end

//
//  Calcultor.m
//  a+b
//

#import "Calcultor.h"

@implementation Calcultor

-(id)init
{
    self = [super init];
    if(self != nil)
    {
        _a = 0;
        _b = 0;
    }
    return self;
}

-(int)add
{
    return _a + _b;
    //NSLog(@"a+b");
}

-(int)sub:(int)a1 andb1:(int)b1;
{
    _a = a1;
    _b = b1;
    return _a + _b;
}
@end