Switching between creative mode and survival mode on minecraft 1.7.5?

Ogres are the hardest mob to kill. Arrows arent working because they are immune so use diamond sword.

Well if you are in survival then an easy way to gain a cases to creative mode is open your world to LAN enabling cheats and then execute the command to change.

If your in single player you have to allow cheats, to do this click escape button and click open LAN and allow cheats. This should enable the permission to switch between game mode 1 and game mode 0.
To do these commands type in the chat /gamemode 1 for creative and /gamemode 0 for survival and to do adventure mode type in /gamemode 2.
Hope this helped! ( best answer? )

The problem is that you don't have permission to use the command. In singleplayer, there's an option to use cheats when creating the world, just go into "more options" and press cheats (usually only once) so that it displays cheats = on. If the world is already created, you can always press ESC and select "open to LAN" and this will give you an option to turn cheats on till you close the world and head back to the menu. Ether way, once you have cheats on, a simple /gamemode 0 or /gamemode 1 (it might be /gamemode creative or /gamemode survival, they plan to take ID's out).

On multiplayer, however, it is almost impossible to switch gamemodes, unless you are Op'ed or have permissions. If you own the server, just go to the console and type in /op (your username). If you are not the owner of the server, you can try asking for the permissions from any admin or owner, as moderators usually don't grant those things. However, asking for OP or permissions is frowned upon on most servers, and in extreme cases can lead to a ban. You can try gaining the owners trust, which usually requires months of playing and some kind of donations on small servers.

On big servers (usually with 100+ people) there's no way ever to change your gamemode.

Hope this helped.