废话不多说，直接上代码
源码如下：
- (BOOL)checkCardNo:(NSString*)cardNo{
if (cardNo.length < 15) {
return NO;
}
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;
}
经本人测试，没有问题，可以放心使用。
