iOS银行卡合法性校验

项目中用到了校验银行卡,就拿来贴上来了

+ (BOOL)checkCardNo:(NSString*)cardNo;//判断银行卡

+ (BOOL)checkCardNo:(NSString*)cardNo{

int oddsum = 0;     //奇数求和

int evensum = 0;    //偶数求和

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;

}