given code lab4 #include <stdio.h>#include <stdlib.h>/* typical C boolean set-up */#define TRUE 1#define FALSE 0typedef struct StackStruct{int* darr; /* pointer to dynamic array */int size; /* amount of space allocated */int inUse; /* top of stack indicator - counts how many values are on the stack */} Stack;void init (Stack* s){s->size = 2;s->darr = (int*) malloc ( sizeof (int) * s->size );s->inUse = 0;}void push (Stack* s, int val){/* QUESTION 7 *//* check if enough space currently on stack and grow if needed *//* add val onto stack */s->darr[s->inUse] = val;s->inUse = s->inUse + 1;}int isEmpty (Stack* s){if ( s->inUse == 0)return TRUE;elsereturn FALSE;}int top (Stack* s){return ( s->darr[s->inUse-1] );}/* QUESTION 9.1 */void pop (Stack* s){if (isEmpty(s) == FALSE)s->inUse = s->inUse - 1;}void reset (Stack* s){/* Question 10: how to make the stack empty? */}int main (int argc, char** argv){Stack st1;init (&st1);push (&st1, 20);push (&st1, 30);push (&st1, 40);push (&st1, 50);while ( isEmpty(&st1) == FALSE){int value = top (&st1);printf ("The top value on the stack is %d\n", value);/* QUESTION 9.2 */pop (&st1);}printf ("The stack is now empty\n");} Q9.1Consider the pop() function in lab4c.c. It is correctly written to take the stack parameter as apointer. Also note that this pop() function only removes the top value from the stack bydecrementing the inUse value. It does NOT remove the top value AND also return the topvalue as is often normally done in a pop() function. (Writing this function to remove and returnthe top value would add way too much complexity to this question. So this code was givenusing a simpler algorithm/variation of pop.)Re-write the pop( ) function from lab4c.c to take a Stack instance as a parameter, modify thisstack instance, and then return an instance of type Stack.The function declaration line is given below for this idea to hopefully clarify this difference inapproach.Stack pop (Stack s) {Q9.2Rewrite the line of code from lab4c.c that would call this modified pop( ) function to reflect thechanges made in Q 9.1.Q10In the program lab4c.c, the function body of reset() does not contain any code.Write the C code that would reset the stack so that it is emptied of all values after the reset( )function is called.

Answered: Consider the pop() function in lab4c.c.…

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Related questions

Question

given code lab4

#include <stdio.h>
#include <stdlib.h>

/* typical C boolean set-up */
#define TRUE 1
#define FALSE 0

typedef struct StackStruct
{
int* darr; /* pointer to dynamic array */
int size; /* amount of space allocated */
int inUse; /* top of stack indicator
- counts how many values are on the stack */
} Stack;

void init (Stack* s)
{
s->size = 2;
s->darr = (int*) malloc ( sizeof (int) * s->size );
s->inUse = 0;
}

void push (Stack* s, int val)
{
/* QUESTION 7 */
/* check if enough space currently on stack and grow if needed */

/* add val onto stack */
s->darr[s->inUse] = val;
s->inUse = s->inUse + 1;
}

int isEmpty (Stack* s)
{
if ( s->inUse == 0)
return TRUE;
else
return FALSE;
}

int top (Stack* s)
{
return ( s->darr[s->inUse-1] );
}

/* QUESTION 9.1 */
void pop (Stack* s)
{
if (isEmpty(s) == FALSE)
s->inUse = s->inUse - 1;
}

void reset (Stack* s)
{
/* Question 10: how to make the stack empty? */

}

int main (int argc, char** argv)
{
Stack st1;

init (&st1);

push (&st1, 20);
push (&st1, 30);
push (&st1, 40);
push (&st1, 50);

while ( isEmpty(&st1) == FALSE)
{
int value = top (&st1);
printf ("The top value on the stack is %d\n", value);

/* QUESTION 9.2 */
pop (&st1);
}

printf ("The stack is now empty\n");
}

Q9.1
Consider the pop() function in lab4c.c. It is correctly written to take the stack parameter as a
pointer. Also note that this pop() function only removes the top value from the stack by
decrementing the inUse value. It does NOT remove the top value AND also return the top
value as is often normally done in a pop() function. (Writing this function to remove and return
the top value would add way too much complexity to this question. So this code was given
using a simpler algorithm/variation of pop.)
Re-write the pop( ) function from lab4c.c to take a Stack instance as a parameter, modify this
stack instance, and then return an instance of type Stack.
The function declaration line is given below for this idea to hopefully clarify this difference in
approach.
Stack pop (Stack s) {
Q9.2
Rewrite the line of code from lab4c.c that would call this modified pop( ) function to reflect the
changes made in Q 9.1.
Q10
In the program lab4c.c, the function body of reset() does not contain any code.
Write the C code that would reset the stack so that it is emptied of all values after the reset( )
function is called.

Expert Solution

Step 1

#include <stdio.h>
#include <stdlib.h>

/* typical C boolean set-up */
#define TRUE 1
#define FALSE 0

typedef struct StackStruct
{
 int*    darr;  /* pointer to dynamic array  */
 int     size;  /* amount of space allocated */
 int     inUse; /* top of stack indicator 
                   - counts how many values are on the stack   */
} Stack;

void init (Stack* s)
{
 s->size = 2;
 s->darr = (int*) malloc ( sizeof (int) * s->size );
 s->inUse  = 0;
}

void push (Stack* s, int val)
{
  /* QUESTION 7 */
  /* check if enough space currently on stack and grow if needed */
  if(s->inUse+1 >= s->size){ //If whole array is inn use i.e inUse +1 = size
      s->size=s->size*2; //Increase the size to 2 times the current
       //Using realloc to resize the size of array, it automatically retains previous elemnts
      s->darr = (int *)realloc(s->darr,(s->size)*sizeof(int));
  }
  
  /* add val onto stack */
  s->darr[s->inUse] = val;
  s->inUse = s->inUse + 1;
}

int isEmpty (Stack* s)
{
  if ( s->inUse == 0)
    return TRUE;
  else
    return FALSE;
}


int top (Stack* s)
{
  return (  s->darr[s->inUse-1] );
}

/* QUESTION 9 */
void pop (Stack* s)
{
  s->inUse = s->inUse - 1;
}

void reset (Stack* s)
{
    s->size=2;
    free(s->darr);
    s->darr = (int*) malloc ( sizeof (int) * s->size );
    s->inUse  = 0;

}

int main (int argc, char** argv)
{
 Stack st1;

 init (&st1);

 push (&st1, 20);
 push (&st1, 30);
 push (&st1, 40);
 push (&st1, 50);
  
 while ( isEmpty(&st1) == FALSE)
   {
    int value = top (&st1);
    printf ("The top value on the stack is %d\n", value);
    
    /* QUESTION 10 */
    pop (&st1);
   }

 printf ("The stack is now empty\n");
}

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