iOS 正则表达式判断3个正数相乘

#import "ViewController.h"
@interface ViewController ()
{
    UITextField *textF;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    textF = [[UITextField alloc] initWithFrame:CGRectMake(100, 200, 200, 30)];
    
    textF.placeholder = @"请输入三个正数相乘";
    textF.borderStyle = UITextBorderStyleRoundedRect;
    
    [self.view addSubview:textF];
    
    
    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(150, 250, 100, 25)];
    
    [btn setTitle:@"验证" forState:UIControlStateNormal];
    
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    
    [btn addTarget:self action:@selector(btnAction) forControlEvents:UIControlEventTouchUpInside];
    
    [self.view addSubview:btn];
    
}


- (void)btnAction {
    
    
    [[UIApplication sharedApplication].keyWindow endEditing:YES];
    
    NSLog(@"%@", [self isThreeNumberMultiply:textF.text] ? @"恭喜你！" : @"输错啦！");
   
}

-(BOOL)isThreeNumberMultiply:(NSString *)str {
    
    NSString *regex = @"[\\d.]*[*][\\d.]*[*][\\d.]*";
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
    return [predicate evaluateWithObject:str];
}

@end