Expert: Zlatko - 11/23/2009

Question
Dear mr ZlatKo

the previous answer help me a lot...

now i facing some problem...

the code i edited is as bellow,
can you check for me and tell me where is the mistake and how to solve it...
tahnk you so much.
the code :

#include <stdio.h>
#include <stdlib.h>
#include<conio.h>
/* self-referential structure */
struct stackNode {
  char* data[15];                  /* define data as an int */
  struct stackNode *nextPtr; /* stackNode pointer */
}; /* end structure stackNode */

struct stackNode1 {
  char* data[15];                  /* define dat1a as an int */
  struct stackNode1 *nextPtr; /* stackNode1 pointer */
}; /* end structure stackNode1 */

typedef struct stackNode StackNode; /* synonym for struct stackNode */
typedef StackNode *StackNodePtr; /* synonym for StackNode* */

typedef struct stackNode1 StackNode1; /* synonym for struct stackNode */
typedef StackNode1 *StackNode1Ptr; /* synonym for StackNode* */

/* prototypes */
void push( StackNodePtr *topPtr, char* info );
void push1( StackNode1Ptr *topPtr, char* info );
char* pop( StackNodePtr *topPtr );
int isEmpty( StackNodePtr topPtr );
void printStack( StackNodePtr currentPtr );
void printStack1( StackNode1Ptr current1Ptr );
int inputString(char* dest, int space);
int i,counter=0;
/* function main begins program execution */
int main( void )
{



  StackNodePtr stackPtr = NULL; /* points to stack top */
  StackNode1Ptr stack1Ptr = NULL; /* points to stack top */


 char value[16];


  clrscr();  /*Clear screen*/
  for(i = 0; i < 10;)
  {
      printf( "Enter [%2d] string: " ,i);
      gets(value);
      if (inputString(value, sizeof(value)) >= sizeof(value))
      {
     printf("Thats too long, try again\n");
      }
      else
      {
     i++;
     counter+=1;
     push( &stackPtr, strdup(value) );
      }
  }
  clrscr();

     for (i=0;i<10;i++)
    printf("%s \n",value[i]);
  for(i=0;i<counter;i++)
  {
  push1( &stack1Ptr, pop( &stackPtr ) );
     printStack1( stack1Ptr );
  }
  getch();
  return 0; /* indicates successful termination */

} /* end main */

/* Insert a node at the stack top */
void push( StackNodePtr *topPtr, char* info )
{
  StackNodePtr newPtr; /* pointer to new node */

  newPtr = malloc( sizeof( StackNode ) );

  /* insert the node at stack top */
  if ( newPtr != NULL ) {
     newPtr->data == *info;
     newPtr->nextPtr = *topPtr;
     *topPtr = newPtr;
  } /* end if */
  else { /* no space available */
     printf( "%s not inserted. No memory available.\n", info );
  } /* end else */

} /* end function push */





void push1( StackNode1Ptr *topPtr, char* info )
{
  StackNode1Ptr newPtr; /* pointer to new node */

  newPtr = malloc( sizeof( StackNode1 ) );

  /* insert the node at stack top */
  if ( newPtr != NULL ) {
     newPtr->data = info;
     newPtr->nextPtr = *topPtr;
     *topPtr = newPtr;
  } /* end if */
  else { /* no space available */
     printf( "%s not inserted. No memory available.\n", info );
  } /* end else */

} /* end function push */

/* Remove a node from the stack top */
char *pop( StackNodePtr *topPtr )
{
  StackNodePtr tempPtr; /* temporary node pointer */
  char* popValue; /* node value */

  tempPtr = *topPtr;
  popValue = ( *topPtr )->data;
  *topPtr = ( *topPtr )->nextPtr;
  free( tempPtr );

  return (popValue);

} /* end function pop */

/* Print the stack */
void printStack( StackNodePtr currentPtr )
{

  /* if stack is empty */
  if ( currentPtr == NULL ) {
     printf( "The stack is empty.\n\n" );
  } /* end if */
  else {
     printf( "The stack is:\n" );

     /* while not the end of the stack */
     while ( currentPtr != NULL ) {
   printf( "%s --> ", currentPtr->data );
   currentPtr = currentPtr->nextPtr;
     } /* end while */

     printf( "NULL\n" );
  } /* end else */

} /* end function printList */


void printStack1( StackNode1Ptr current1Ptr )
{

  /* if stack is empty */
  if ( current1Ptr == NULL ) {
     printf( "The stack is empty.\n\n" );
  } /* end if */
  else {
     printf( "The reversed stack is:\n" );

     /* while not the end of the stack */
     while ( current1Ptr != NULL ) {
   printf( "%s --> ", current1Ptr->data );
   current1Ptr = current1Ptr->nextPtr;
     } /* end while */

     printf( "NULL\n" );
  } /* end else */

} /* end function printList */




/* Return 1 if the stack is empty, 0 otherwise */
int isEmpty( StackNodePtr topPtr )
{
  return topPtr == NULL;

} /* end function isEmpty */



int inputString(char* dest, int space)
{
  int count = 0;
  if (dest == NULL || space == 0) return 0;

  while(1)
  {
      char c = getc(stdin);
      if (c == '\n' || c == EOF)
      {
          if (space) *dest = 0;
          break;
      }

      ++count;
      if (space > 1)
      {
          *dest++ = c;
          --space;
      }
      if (space == 1)
      {
          *dest = 0;
          --space;
      }
  }
  return count;
}


the error is mismatch parameter in push and Lvalue is require.
may i know what is lvalue and how to solve the code.
Thank.  

Answer
Canno, I don't have much time right now to look at your problem. I will look at it later today. But I repeat that you should remove all redundant code referring to stack node 1

Remove

struct stackNode1 {
 char* data[15];                  /* define dat1a as an int */
 struct stackNode1 *nextPtr; /* stackNode1 pointer */
}; /* end structure stackNode1 */

typedef struct stackNode1 StackNode1; /* synonym for struct stackNode */
typedef StackNode1 *StackNode1Ptr; /* synonym for StackNode* */

and all functions working with stackNode1

They are redundant. They are not necessary. You use struct stackNode, StackNode, and StackNodePtr data types for BOTH stacks.


The char* data[15] should be just char* data;. The memory storing the string data will be allocated by strdup. Look closely for the strdup in the input loop I gave you in my last answer.

I will look more at your problem in about 10 hours from now.

Best regards
Zlatko



EDIT:

Canno, I've looked at your code, and mostly it just needed the stackNode1 stuff to be deleted. It had a few small logic errors. I fixed them for you but you really need to learn how to read compiler errors and warnings. You should also learn how to trace through your code with a debugger. Once again, my changes are marked with /*XXX

I gave the program a quick test. It is up to you to test further.

Bye.


#include <stdio.h>
#include <stdlib.h>
#include<conio.h>
#include <string.h> /*XXX added for strdup */


/* self-referential structure */
struct stackNode {
   char* data;    /*XXX changed */              /* define data as an int */
   struct stackNode *nextPtr; /* stackNode pointer */
}; /* end structure stackNode */

typedef struct stackNode StackNode; /* synonym for struct stackNode */
typedef StackNode *StackNodePtr; /* synonym for StackNode* */


/* prototypes */
void push( StackNodePtr *topPtr, char* info );
char* pop( StackNodePtr *topPtr );
int isEmpty( StackNodePtr topPtr );
void printStack( StackNodePtr currentPtr );
int inputString(char* dest, int space);
int i,counter=0;
/* function main begins program execution */
int main( void )
{



   StackNodePtr stackPtr = NULL; /* points to stack top */
   StackNodePtr stack1Ptr = NULL; /* points to stack top */


   char value[16];


   clrscr();  /*Clear screen*/
   for(i = 0; i < 10;)
   {
       printf( "Enter [%2d] string: " ,i);
       /*XXX gets(value); you don't need gets(value), the inputString routine handles input */
       if (inputString(value, sizeof(value)) >= sizeof(value))
       {
           printf("Thats too long, try again\n");
       }
       else
       {
           i++;
           counter+=1;
           push( &stackPtr, strdup(value) );
       }
   }
   clrscr();

   /*XXX you don't need this, value is a single string, not an array of strings
   for (i=0;i<10;i++)
   printf("%s \n",value[i]);
   */
   printStack( stackPtr ); /*XXX instead, I think you want this */

   for(i=0;i<counter;i++)
   {
       push( &stack1Ptr, pop( &stackPtr ) );
       printStack( stack1Ptr );
   }
   getch();
   return 0; /* indicates successful termination */

} /* end main */

/* Insert a node at the stack top */
void push( StackNodePtr *topPtr, char* info )
{
   StackNodePtr newPtr; /* pointer to new node */

   newPtr = malloc( sizeof( StackNode ) );

   /* insert the node at stack top */
   if ( newPtr != NULL ) {
       newPtr->data = info; /*XXX storing info, not *info, we are storing the pointer to the string, also changed == to = */
       newPtr->nextPtr = *topPtr;
       *topPtr = newPtr;
   } /* end if */
   else { /* no space available */
       printf( "%s not inserted. No memory available.\n", info );
   } /* end else */

} /* end function push */

/* Remove a node from the stack top */
char *pop( StackNodePtr *topPtr )
{
   StackNodePtr tempPtr; /* temporary node pointer */
   char* popValue; /* node value */

   tempPtr = *topPtr;
   popValue = ( *topPtr )->data;
   *topPtr = ( *topPtr )->nextPtr;
   free( tempPtr );

   return (popValue);

} /* end function pop */

/* Print the stack */
void printStack( StackNodePtr currentPtr )
{

   /* if stack is empty */
   if ( currentPtr == NULL ) {
       printf( "The stack is empty.\n\n" );
   } /* end if */
   else {
       printf( "The stack is:\n" );

       /* while not the end of the stack */
       while ( currentPtr != NULL ) {
           printf( "%s --> ", currentPtr->data );
           currentPtr = currentPtr->nextPtr;
       } /* end while */

       printf( "NULL\n" );
   } /* end else */

} /* end function printList */



/* Return 1 if the stack is empty, 0 otherwise */
int isEmpty( StackNodePtr topPtr )
{
   return topPtr == NULL;

} /* end function isEmpty */



int inputString(char* dest, int space)
{
   int count = 0;
   if (dest == NULL || space == 0) return 0;

   while(1)
   {
       char c = getc(stdin);
       if (c == '\n' || c == EOF)
       {
           if (space) *dest = 0;
           break;
       }

       ++count;
       if (space > 1)
       {
           *dest++ = c;
           --space;
       }
       if (space == 1)
       {
           *dest = 0;
           --space;
       }
   }
   return count;
}