PUSH AN ELEMENT IN STACK USING ARRAY

#include<conio.h>
#include<stdio.h>
#define MAX 5

int st[MAX];
int top=-1;

void push(int st[],int val);
int pop(int st[]);
int pep(int st[]);
void display( int st[] );

void main()

{
int option ,val;
clrscr();
do{
printf("\n main menu\n");
printf("\n1:PUSH\n");
printf("\n2:POP\n");
printf("\n3:PEEP\n");
printf("\n4:DISPLAY");
printf("\n5:EXIT");
printf("\nenter your option:   ");
scanf("%d",&option);

switch(option)
{
case 1: printf("\n enter value to insert in stack\n");
    scanf("%d",&val);
    push(st,val);
    break;

case 2: val=pop(st);

         if(val!=-1)
        // printf("\n underflow");
         //else
         printf("\n %d deleted from the stack ",val);

       break;
case 3: val=pep(st);
       if(val!=-1)
       printf("\n%d is stored at top ",val);
       break;

case 4: display(st);
    break;
case 5:exit(0);
default :
printf("not a correct option") ;
}
}
while(option!=5);
getch();

}

void push(int st[],int val)
{
if(top==MAX-1)
{
printf("\nover flow");
}
else
{
top++;
st[top]=val;
}
}

int pop(int st[])
{
int val;
   if(top==NULL)
   {
   printf("\nunder flow");
   }
   else
   {
   val=st[top];
   top--;
   }
   return val;
   }

   int pep(int st[])
   {
   if(top==-1)
   {
   printf("\nstack is empty");
   return-1;
   }
   else
{
return(st[top]) ;
}
}

    void display(int st[])
    {
    int i;
    if(top==NULL)
    {
    printf("\nstack is empty");
    }
    else
    {
    for(i=top;i>=0;i--)

    {
    printf("\n%d",st[i]);
    }

    }
    }