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];

}