int main()
{
int item, choice;
char ans;
st.top=-1;
puts("Implementation of Stack");
do{
puts("1. Push \n2. Pop \n3. Display");
scanf(" %d%*c", &choice);
switch(choice){
case 1:
puts("Enter item to push:");
scanf(" %d%*c", &item);
if(stfull()) puts("Stack Overflow!");
else push(item);
break;
case 2:
if(stempty()) puts("Stack Underflow!");
else printf("Popped element: %d", pop());
break;
case 3:
display();
break;
}
puts("Continue?");
scanf(" %c%*c", &ans);
} while(ans=='Y' || ans=='y');
return 0;
}
void bintree<T>::preorder(node *root)
{
node *current,*s[10];
int top=-1;
if(root==NULL)
{
cout<<"\n The Tree is empty"<<endl;
return;
}
current=root;
for(;;)
{
while(current!=NULL)
{
cout<<" "<<current->data;
push(current,&top,s);
current=current->left;
}
if(!stempty(top))
{
pop(&top,s,¤t);
current=current->right;
}
else
return;
}
}
void bintree<T>::postorder(node *root)
{
struct stack
{
node *element;//Here placing the node containing value
int check;//check 1 means visiting left subtree
//check 0 means visiting right subtree
}st[10];
int top=-1;
node *current;
if(root==NULL)
{
cout<<"\n The Tree is empty"<<endl;
return;
}
current=root;
for(;;)
{
while(current!=NULL)
{
top++;
st[top].element=current;
st[top].check=1;//visiting the left subbranch
current=current->left;
}
while(st[top].check==0)
{
current=st[top].element;
top--;
cout<<" "<<current->data;
if(stempty(top))
return;
}
current=st[top].element;//pushing the element onto the stack
current=current->right;
st[top].check=0;//visiting right subtree
}
}
void display()
{
int i;
if(stempty()) puts("Stack Underflow!");
else for(i=st.top; i>=0; i--) printf(" %d ", st.s[i]);
}
