Stack using array code in C

#include<stdio.h>

#include<stdlib.h>

#define size 10void Push();
void Pop();
void Display();
int CheckStackFull();
int CheckStackEmpty();
struct StackArray
{
 int array[size],top;

}
ptr;
int main()
{
 int choice,contin;
 ptr.top=-1;
 do
{
 printf("Enter\n1 - Push\n2 - Pop\n3 - Display\n4 - Exit\n");
 scanf("%d",&choice);
 switch(choice) 
{
 case 1: Push();
 break;
 case 2: Pop();
 break;
 case 3: Display();
break;
 case 4: exit(0);
 break;
 default: printf("Enter Valid Choice\n");
break;
 
}
 printf("Enter 1 to continue otherwise any other number\n");
 scanf("%d",&contin);
 
}
while(contin==1);
 return(0);

}
void Push()
{
 int flag=CheckStackFull();
 if(flag==1) 
{
 int value;
 printf("Enter value to push into stack\n");
 scanf("%d",&value);
 ptr.top+=1;
 ptr.array[ptr.top]=value;
 
}
 else 
{
 printf("Stack is Full\n");
 
}

}
void Pop()
{
 int flag=CheckStackEmpty();
 if(flag==1) 
{
 printf("Popped Element is %d\n",ptr.array[ptr.top]);
 ptr.top-=1;
 
}
 else 
{
 printf("Stack is Empty\n");
 
}

}
void Display()
{
 int i,flag=CheckStackEmpty();
 if(flag==1) 
{
 printf("Elements present in stack\n");
 for(i=ptr.top;i>-1;i--) printf("%d\n",ptr.array[i]);
 printf("\n");
 
}
 else 
{
 printf("Stack is Empty\n");
 
}

}
int CheckStackFull()
{
 if(ptr.top==size-1) return 0;
 else return 1;

}
int CheckStackEmpty()
{
 if(ptr.top==-1) return 0;
 else return 1;

}