进制转换iOS

16进制转10进制

int a =  strtoul([@"16进制的字符串" UTF8String], 0, 16);

 下面这种方法防止内存溢出   

unsigned long a = 0;

NSScanner *scanner = [NSScanner scannerWithString:@"16进制字符串"];

[scanner scanHexLongLong:&a];

 

10进制转16进制

NSString *hexString = [NSString stringWithFormat:@"%@",[[NSString alloc] initWithFormat:@"%1lx",a]];