Const modifier causes data to be placed in ROm - check on this struct player{ unsigned char Xpos; unsigned char Ypos; unsigned short Score; }; typedef struct player playerType; // defines playerType as a type of data object with properties of struct player playerType Sprite; // declares Sprite as data object of type playerType //initialize properties of Sprite: Sprite.Xpos = 10; Sprite.Ypos = 10; Sprite.Score = 1000; //initialize array of structures: playerType Ships[10]; unsigned long i; Ships[i].Xpos = 10; .....