#import <Foundation/Foundation.h>  int main() {  // ? == {0,1}  // * == {0,無窮}  // ＋ == {1,無窮}  // d == [0-9]  // w == [A-Za-z_0-9]  // * 的意思是可有可無  // [a|b|c]+ 表示三個(gè)至少出現(xiàn)一次或多次  //檢測電話號碼是否正確  NSString *tel = @"";  //正則表達(dá)式  NSString *regex = @"^\d*$";  // NSString *regex = @"^[0-9]{3,4}-[0-9]{7,8}$";  NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",regex];//創(chuàng)建需要滿足上面的正則表達(dá)式的謂詞  NSLog(@"該電話號碼:%d",[predicate evaluateWithObject:tel]);  //用戶名 （第一位必須是字母，6-16位，只能有字母，數(shù)字或下劃線）  NSString *user = @"m54355";  NSString *regex1 = @"^[A-Za-z]\w{5,15}$";  NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",regex1];  // NSLog(@"該電話號碼:%d",[predicate1 evaluateWithObject:user]);  // //身份證  // NSString *user1 = @"610125199301300814";  // NSString *regex2 = @"^\d{17}[\dxX]$";  // NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",regex2];  // NSLog(@"該身份證:%d",[predicate2 evaluateWithObject:user1]);  //郵箱  NSString *mailbox = @"101707383@qq.com";  NSString *regex3 = @"^[a-zA-Z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$";  NSPredicate *predicate3 = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",regex3];  // NSLog(@"該郵箱:%d",[predicate3 evaluateWithObject:mailbox]);  //手機(jī)號  // NSString *phone = @"18709259205";  // NSString *regex4 = @"^1[3|4|5|7|8]\d{9}$";  // NSPredicate *predicate4 = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",regex4];  // NSLog(@"該手機(jī):%d",[predicate4 evaluateWithObject:phone]);  if ([predicate1 evaluateWithObject:user] == 1) {  if ([predicate3 evaluateWithObject:mailbox] == 1) {  NSLog(@"登錄成功");  }  }else{  NSLog(@"錯誤");  }  return 0;  }