stack not getting updated after performing operations - arrays

Question

I m trying to implement stack using array and performing basic operations on it. All my operations are performing well. But the issue is when i again try to do the same operation, it seems like they are begin performed on the same old stack and not the updated one after the performing the operations.
for e.g when i push an element in the stack and then try to display the stack , it doesn't display's the pushed element. The same happens with pop() as well every time it shows the same element begin popped out.
Here's my C code for stack:
#include <stdio.h>
#define MAXSIZE 15
int stack[MAXSIZE];
int top = -1;
void push(int x)
{
if (top == MAXSIZE - 1)
{
printf("Overflow Condition");
}
else
{
top++;
stack[top] = x;
}
}
void pop()
{
int item;
if (top == -1)
{
printf("Underflow Condition\n");
}
else
{
item = stack[top];
top--;
printf("The popped element is: %d", item);
}
}
void peek()
{
if (top == -1)
{
printf("Underflow Condition\n");
}
else
{
printf("%d", stack[top]);
}
}
void displayStack()
{
int i;
for (i = top; i >= 0; i--)
{
printf("%d ", stack[top]);
top--;
}
}
int main()
{
// Push the starting element:
push(2);
push(3);
push(4);
push(5);
push(6);
int ch, a;
printf("Enter Choice: \n 1: push\n 2: pop\n 3: peek\n 4: display \n\n");
scanf("%d", &ch);
switch (ch)
{
case 1:
printf("Enter the element you want to push to stack: ");
scanf("%d", &a);
push(a);
break;
case 2:
pop();
break;
case 3:
peek();
break;
case 4:
displayStack();
break;
default:
printf("Invalid Choice...");
}
}
Any idea what's the matter??

Answer 1

Try to replace your displayStack() function with this:
void displayStack()
{
int i;
for (i = top; i >= 0; i--)
{
printf("%d ", stack[i]);
}
}
You should not modify a data structure inside an output function. Everything else seems fine.