16进制格式的OC字符串转成int类型

        NSString *color = @"0xff3322";
        int num = 0;
        const char * str = [color cStringUsingEncoding:NSUTF8StringEncoding];
        sscanf(str, "%x", &num);
        NSLog(@"%d", num);

//num中保存的就是转化完成的int类型数据