C program to implement stack using array and using structure.

Stack is called as an ADT that is Abstract Data Type. ADT is user defined data type which is combination of built in data type with some legal functions. Stack is implemented using array and some legal functions like push(), pop(). Stack is also implemented using linked list also.


This is the implementation of stack using array.
Please include stdio.h, conio.h ans stdlib.h header files and a symbolic constant # define MAX 10 before main function.
#include
#include
#include
#define MAX 10

void push (void);
void pop (void);
int isfull (void) ;
int isempty (void);
void display(void);


struct stack
{
int it[MAX];
int top;
} s;

void main(void)
{
int ch;
s.top=-1;
clrscr();
do
{
printf("\n1.push \n 2.pop \n 3.display \n 4.exit\n");
printf("\n\n Enter your choice\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
push();
break;
case 2:
pop();
break;
case 3:
display();
break;
case 4:
exit(0);
default:
printf("\n invalid choice\n");
}
}while(ch<=4);
getch();
}

int isfull (void)
{
if(s.top== MAX -1)
{
return(1);
}
else
{
return(0);
}
}

int isempty (void)
{
if(s.top==-1)
{
return(1);
}
else
{
return(0);
}
}
void push (void)
{ int x;
if(isfull()==1)
{
printf("\n\n stack is full\n");
}
else
{
s.top=s.top+1;
printf("\n\nEnter the element\n");
scanf("%d",&x);
s.it[s.top]=x;
printf("\n\n%d is pushed",s.it[s.top]);
}
}
void pop (void)
{
if(isempty()==1)
{
printf("\n\n stack is empty\n");
}
else
{
printf("\n\n %d is poped", s.it[s.top]);
s.top=s.top-1;
}
}

void display(void)
{
int i;
if(isempty()==1)
{
printf("\n\n stack is empty\n");
}
else
{
printf("\nElements of stack are as follows\n");
for(i=s.top;i>=0;i--)
{
printf("%d ",s.it[i]);
}
}
}

Below is the program which implement the stack using linked list.
Please include stdio.h, conio.h, stdlib.h and alloc.h header files and a symbolic constant #define NULL 0 before main function.
#define NULL 0
#include
#include
#include
#include
void push (void);
void pop (void);
void display(void);
struct stack
{
int no;
struct stack * next;
};
typedef struct stack node;
node *top,*tp;
void main(void)
{
int ch;
top=NULL;
clrscr();
do
{
printf("\n1.Push\n2.Pop\n3.Display\n4.Exit\n");
printf("\n Enter your choice\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
push();
break;
case 2:
pop();
break;
case 3:
display();
break;
case 4:
exit(0);
default:
printf("\ninvalid choice\n");
}
}while(ch<5);
getch();
}
void push(void)
{
int num;
tp=(node*)malloc(sizeof(node));
if(tp==NULL)
{
printf("\n\n stack is full\n");
}
else
{
printf("\n\nEnter the number\n");
scanf("%d",&tp ->no);
tp->next=top;
top=tp;
}
}
void pop (void)
{
if(top==NULL)
{
printf("\n\n stack is empty\n");
}
else
{
tp=top;
top=top->next;
printf("\n\n number deleted is %d",tp->no);
free(tp);
}
}
void display(void)
{
printf("\nElements of stack are as follows\n");
tp=top;
if(top==NULL)
{
printf("\n\n no element is available in stack\n");
}
else
{
do
{
printf("%d ",tp->no);
tp=tp->next;
}while(tp!=NULL);
}
}