把开发过程中比较好的内容段做个收藏，如下的内容是关于 ios开发中各种版本、设备的区分的内容。

if ([modelname isEqualToString:@"iPhone"]) {
}
if ([modelname isEqualToString:@"IPod Touch"]) {
}
if ([modelname isEqualToString:@"iPhone Simulator"]) {
}

也可以通过宏定义区分

#if TARGET_OS_IPHONE
#endif

#if TARGET_IPHONE_SIMULATOR
#endif

#if !TARGET_IPHONE_SIMULATOR
#endif

ios设备版本的区分-iphone3gs,iphone4....ios提供了几种c函数来获得相应信息如下

struct utsname u;

if ([machine isEqualToString:@"iPhone1,1"]) {
}
if ([machine isEqualToString:@"iPhone1,2"]) {
}
if ([machine isEqualToString:@"iPhone2,1"]) {
}
if ([machine isEqualToString:@"iPod1,1"]) {
}
if ([machine isEqualToString:@"iPod2,1"]) {
}
if ([machine isEqualToString:@"iPod3,1"]) {
}

或者

{
  size_t size;
  sysctlbyname("hw.machine", NULL, &size, NULL, 0);

  Possible values:
  "iPhone1,1" = iPhone 1G
  "iPhone1,2" = iPhone 3G
  "iPhone2,1" = iPhone 3GS
  "iPod1,1"   = iPod touch 1G
  "iPod2,1"   = iPod touch 2G

  free(machine);
  return platform;
}