Answer P27

P27 Answer

**ppv   = 99

#include  <stdio.h> 

void main ( void )
{
  int value, num = 99 ;
  int *pv= &value, *pn = &num ;
  int **ppv= &pv ;
 
  **ppv = *pn;  /* ugly statement */

  printf("**ppv   = %d\n", **ppv );

}

The statement

calls for an L-value (a location) on the left of the assignment operator and calls for an R-value (an integer in this case) on the right of the assignment operator.

It helps to remember that assignment statements happen in two big steps:

1. Evaluate the right-hand side to get a value.
   • here, this means follow the pointer value in pn to the location that holds 99
2. Put the value in the location indicated by the left-hand side
   • here, this means follow the pointers (hop, hop) **ppv to the variable value