The C buttons are four small, yellow buttons found on the top right area of a Nintendo 64 controller. All four buttons are used for jumping when fighting, and are used to change colors on the character selection screen.
Main article: C-Stick
The Nintendo GameCube controller's equivalent of the N64's C buttons is the C-Stick, which is used in Super Smash Bros. Melee's VS. Mode and if playing on a GC controller in Super Smash Bros. Brawl to activate uncharged smash attacks. If playing in single player in Melee, it adjusts the camera zoom.