#pragma mark 判断身份证号是否合法
- (BOOL)judgeIdentityStringValid:(NSString *)identityString {
  if (identityString.length != 18) return NO;
  // 正则表达式判断基本 身份证号是否满足格式
  NSString *regex2 = @"^(^[1-9]\\d{7}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])\\d{3}$)|(^[1-9]\\d{5}[1-9]\\d{3}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])((\\d{4})|\\d{3}[Xx])$)$";
  NSPredicate *identityStringPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];
  //如果通过该验证，说明身份证格式正确，但准确性还需计算
  if(![identityStringPredicate evaluateWithObject:identityString]) return NO;
  //** 开始进行校验 *//
  //将前17位加权因子保存在数组里
  NSArray *idCardWiArray = @[@"7", @"9", @"10", @"5", @"8", @"4", @"2", @"1", @"6", @"3", @"7", @"9", @"10", @"5", @"8", @"4", @"2"];
  //这是除以11后，可能产生的11位余数、验证码，也保存成数组
  NSArray *idCardYArray = @[@"1", @"0", @"10", @"9", @"8", @"7", @"6", @"5", @"4", @"3", @"2"];
  //用来保存前17位各自乖以加权因子后的总和
  NSInteger idCardWiSum = 0;
  for(int i = 0;i  17;i++) {
    NSInteger subStrIndex  = [[identityString substringWithRange:NSMakeRange(i, 1)] integerValue];
    NSInteger idCardWiIndex = [[idCardWiArray objectAtIndex:i] integerValue];
    idCardWiSum      += subStrIndex * idCardWiIndex;
  }
  //计算出校验码所在数组的位置
  NSInteger idCardMod=idCardWiSum%11;
  //得到最后一位身份证号码
  NSString *idCardLast= [identityString substringWithRange:NSMakeRange(17, 1)];
  //如果等于2，则说明校验码是10，身份证号码最后一位应该是X
  if(idCardMod==2) {
    if(![idCardLast isEqualToString:@"X"]||[idCardLast isEqualToString:@"x"]) {
      return NO;
    }
  }else{
    //用计算出的验证码与最后一位身份证号码匹配，如果一致，说明通过，否则是无效的身份证号码
    if(![idCardLast isEqualToString: [idCardYArray objectAtIndex:idCardMod]]) {
      return NO;
    }
  }
  return YES;
}

#pragma mark 判断银行卡号是否合法
-(BOOL)isBankCard:(NSString *)cardNumber{
  if(cardNumber.length==0){
    return NO;
  }
  NSString *digitsOnly = @"";
  char c;
  for (int i = 0; i  cardNumber.length; i++){
    c = [cardNumber characterAtIndex:i];
    if (isdigit(c)){
      digitsOnly =[digitsOnly stringByAppendingFormat:@"%c",c];
    }
  }
  int sum = 0;
  int digit = 0;
  int addend = 0;
  BOOL timesTwo = false;
  for (NSInteger i = digitsOnly.length - 1; i >= 0; i--){
    digit = [digitsOnly characterAtIndex:i] - '0';
    if (timesTwo){
      addend = digit * 2;
      if (addend > 9) {
        addend -= 9;
      }
    }
    else {
      addend = digit;
    }
    sum += addend;
    timesTwo = !timesTwo;
  }
  int modulus = sum % 10;
  return modulus == 0;
}