All major scales are the same. The C major scale specifically however is relevant in music theory because it is the most "basic". On a piano, the scale is simply all of the white keys played in order from C. None of the black keys are used as there are no sharps or flats in that scale.

A Major scale is made by following the pattern: w-w-h-w-w-w-h
(w=whole step, h=half step).

It gives you an easy view and understanding on how major scales are made. They are all made with this pattern, but all the others have sharps since jumping a whole or half step may put you on one of those notes.