Turbo C example of program that implements Stack?

Answer 1

/*Linked List Implementation of STACK*/

/*Checking of parenthesis in expressions*/

#include<conio.h>

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#define M 100

typedef struct node *nd;

struct node

{

char p;

nd next;

}NODE;

void getExpression(char expr[]);

void checkParenthesis(char expr[],int *);

void dispResult(int);

nd top,bottom;

int main(void)

{

char expr[M];

int r;

getExpression(expr);

checkParenthesis(expr,&r);

dispResult(r);

return 0;

}

void getExpression(char expr[])

{

clrscr();

printf("Input an expression: ");

gets(expr);

}

void checkParenthesis(char expr[],int *r)

{

int f=0,l,i;

char e;

nd tp,t;

top = NULL;

bottom = NULL;

l = strlen(expr);

for(i=0;i<l;i++)

{

e=expr[i];

if(e == '(')

{

tp = malloc(sizeof(NODE));

tp->p=e;

if((top==NULL) && (bottom==NULL))

{

tp->next = NULL;

top = tp;

bottom = tp;

}

else

{

tp->next=top;

top=tp;

tp=NULL;

}

}

else if(e==')')

{

if(top==bottom)

{

if(top==NULL)

{

f=1;

break;

}

else

{

top=NULL;

bottom=NULL;

}}

else

{

t=top;

top=top->next;

t->next=NULL;

}

}

}/*end of for loop*/

if(top != NULL)

f=1;

*r=f;

}/*end of function checkParenthesis*/

void dispResult(int r)

{

clrscr();

if(r==0)

printf("The expression has a balance parentheses.");

else if(r>0)

printf("Unbalanced parentheses.");

getch();

}

/*

if(top==bottom)

{

top=NULL;

bottom=NULL;

}

else

{

if((top==NULL)&&(bottom==NULL))

{

f=1;

break;

}

else

{

t =top;

top = top->next;

t->next = NULL;

}

}

}

*/

/*eahjie*/