ios随机数

13~16之间的随机数
x=arc4random()%4+13
m~n之间的随机数
x = arc4random()%(n-m+1)+m

随机数公式.png

练习一

随机数练习.png

@interface ViewController ()
{
    int randomNumber;
}
@property (weak, nonatomic) IBOutlet UITextField *inputTextField;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    randomNumber = arc4random()%100+1;
}

- (IBAction)clickButton:(UIButton *)sender {

    int numberInputed = [self.inputTextField.text intValue];
    NSLog(@"%d",randomNumber);
    if (numberInputed > randomNumber)
    {
        [sender setTitle:@"大了，再猜"forState:UIControlStateNormal];
    }
    else if (numberInputed < randomNumber)
    {
        [sender setTitle:@"小了，再猜"forState:UIControlStateNormal];
    }
    else
    {
        [sender setTitle:@"恭喜，猜对了。重来"forState:UIControlStateNormal];
        randomNumber = arc4random()%100+1;
    }
}

程序重构

-(NSString *)getGuessResult
{
    return (numberInputed > randomNumber) ? @"大了，再猜" : (numberInputed < randomNumber) ? @"小了，再猜" :((void)(randomNumber = [self makeNewRandom]),@"恭喜，猜对了。重来");
    
}

- (IBAction)clickButton:(UIButton *)sender {

    numberInputed = [self.inputTextField.text intValue];
    NSLog(@"%d",randomNumber);
    [sender setTitle:[self getGuessResult] forState:UIControlStateNormal];
}