There is no portable way to do this (unless you use a lib like NCurses). Anything you do will be platform specific. Are you on Windows?
Besides, it's a user setting, which means you probably shouldn't mess with it. Many people -- particularly those that use the console frequently -- configure their console to look a certain way. It's annoying when programs throw away your preferences and substitute their own.
Right click on the title bar of your console window, go to "Defaults"
Select the "Font" tab - change the font size.
Go to the "Layout" tab - change the window size.
Hit OK
so are you saying there is no way to do I though code?
I'm not saying that. You can do this through code (though on Windows, it's difficult). What I'm saying is that you shouldn't because people have their own settings that they prefer. Just because you like your font bigger does not mean other people will.
Good programs respect other user's personal preferences and do not disregard them to substitute in their own.
As for doing it through code... WinAPI has a "SetConsoleFont" function, but it appears to be 'undocumented' so I'm having trouble finding it on MSDN... and this is a big sign that it's probably not a good idea to use this function. But I'll see if I can dig up some examples anyway.