jackson6612, your error message is an indication as to what's wrong with your logic in the code.

in the prototype for display:
Code:
void display(Student dummystud[]);
you tell display to accept an array of Student type.

this means there is more than one struct you want to iterate over right? however in your definition you don't have your code do that.

In essence you need to make sure your display function goes over all the Student structures not just one or the first one.

Code:
void diplay (Student dummystud[]){     
  
        for each struct in the array:
           display dummystudNum.data
        
}