判斷銀行帳號是否輸入正確，判斷銀行帳號輸入

判斷銀行帳號是否輸入正確，判斷銀行帳號輸入

不多說  直接貼代碼   隨便輸入銀行卡號就可以進行判斷

- (void)viewDidLoad {    [super viewDidLoad];    NSString *str = @"6226820011200783033";    BOOL isRight = [self checkCardNo:str];    if (!isRight) {                UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"不對" message:@"請重新輸入卡號" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil, nil];        [alert show];    }else{        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"對" message:@"" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil, nil];        [alert show];}}

//這就是判斷方法   

- (BOOL) checkCardNo:(NSString*) cardNo{    int oddsum = 0;     //奇數求和    int evensum = 0;    //偶數求和    int allsum = 0;    int cardNoLength = (int)[cardNo length];    int lastNum = [[cardNo substringFromIndex:cardNoLength-1] intValue];        cardNo = [cardNo substringToIndex:cardNoLength - 1];    for (int i = cardNoLength -1 ; i>=1;i--) {        NSString *tmpString = [cardNo substringWithRange:NSMakeRange(i-1, 1)];        int tmpVal = [tmpString intValue];        if (cardNoLength % 2 ==1 ) {            if((i % 2) == 0){                tmpVal *= 2;                if(tmpVal>=10)                    tmpVal -= 9;                evensum += tmpVal;            }else{                oddsum += tmpVal;            }        }else{            if((i % 2) == 1){                tmpVal *= 2;                if(tmpVal>=10)                    tmpVal -= 9;                evensum += tmpVal;            }else{                oddsum += tmpVal;            }        }    }        allsum = oddsum + evensum;    allsum += lastNum;    if((allsum % 10) == 0)        return YES;    else        return NO;}