C Program for Stack Operations – Using Array

#define SIZE 5            /* Size of Stack */
int s[SIZE],top=-1;       /* Global declarations */
 
push(int elem)
{                       /* Function for PUSH operation */
if( Sfull()) printf("\n\n Overflow!!!!\n\n");
else
{
++top;
s[top]=elem;
}
}
 
int pop()
{                      /* Function for POP operation */
int elem;
if(Sempty()){ printf("\n\nUnderflow!!!!\n\n");
return(-1); }
else
{
elem=s[top];
top--;
return(elem);
}
}
 
int Sfull()
{                     /* Function to Check Stack Full */
if(top == SIZE-1) return 1;
return 0;
}
 
int Sempty()
{                    /* Function to Check Stack Empty */
if(top == -1) return 1;
return 0;
}
 
display()
{                  /* Function to display status of Stack */
int i;
if(Sempty()) printf(" \n Empty Stack\n");
else
{
for(i=0;i<=top;i++)
printf("%d\n",s[i]);
printf("^Top");
}
}
 
main()
{                         /* Main Program */
int opn,elem;
do
{
clrscr();
printf("\n ### Stack Operations ### \n\n");
printf("\n Press 1-Push, 2-Pop,3-Display,4-Exit\n");
printf("\n Your option ? ");
scanf("%d",&opn);
switch(opn)
{
case 1: printf("\n\nRead the element to be pushed ?");
scanf("%d",&elem);
push(elem); break;
case 2: elem=pop();
if( elem != -1)
printf("\n\nPopped Element is %d \n",elem);
break;
case 3: printf("\n\nStatus of Stack\n\n");
display(); break;
case 4: printf("\n\n Terminating \n\n"); break;
default: printf("\n\nInvalid Option !!! Try Again !! \n\n");
break;
}
printf("\n\n\n\n  Press a Key to Continue . . . ");
getch();
}while(opn != 4);
}