text: /*	CP09_15.C	*/
  /*	Example of Call by Reference Method*/
  #include<stdio.h>
  #include<conio.h>
  int Exp(int, int ); //Function Prototype
  
  int main()
  {
   int x,y, value;
   int (*ptof)(int, int ); //Pointer to function Declaration
   ptof = &Exp;            // ptof points to Exp(int, int)
  
   printf("Enter x and y: ");
   scanf("%d %d",&x, &y);
   value= (*ptof)(x, y);   // Function call using pointer 
   printf("\nx*x+2*x*y+y*y = %d", value);
  }
  
  int Exp(int x, int y)
  {
   return (x*x+2*x*y+y*y);
  }
  