Spreading code over multiple cpp files

I am a begginer to c++ though not to programming in general. One problem I have run in to is how to access a something from one source code to another. In functions, I set the object as a parameter then access it with relative ease but if I have my own object: typedef struct tagCam { float xpos, ypos, zpos; float yrot, lookupdown; } CAM; I have had to place it in both files for CAM to be detected. How can I do it so that I need only to place it in one? Is it through header files? If so I will need a little explaining... Thanks...