strange behaviour of cout? - pointers

Question

In a long assignment I found a miraculous behaviour of cout!!
`
for(i=0; i<ndel; i++)
{
cin>>a;
head=Delete(head, a);
cout<<"Deleting ";
cout<<a<<endl;
//cout<<"Deleting "<<a<<endl; /*this gives seg error*/
printInts(head);
}
`
The code works fine with
cout<<a<<endl;
but gives a segmentation fault with
cout<<"Deleting "<<a<<endl;
Here's my Delete function:
node* Delete(node *T, int a)
{
if(a==1 && T!=NULL)
{
T->flag=0;
return T;
}
int arr[50];
int n, i, tr_num; /* tr_num is the index of array corresponding to last node not to be deleted if the no. to be del is leaf*/
node *tr, *ptr; /*tr istracker on last pointer that cannot be deleted if it encounters leaf*/
node *pth[50];
n=find_binary(arr, a);
tr=T;
ptr=T;
pth[0]=T;
tr_num=0;
for(i=0; i<n-1; i++)
{
if(arr[n-2-i]==0)
{
if(ptr->left==NULL)
{
return T;
}
ptr=ptr->left;
pth[i+1]=ptr;
if((ptr->flag==1 && (ptr->right!=NULL || ptr->left!=NULL)) || (ptr->right!=NULL && ptr->left!=NULL))
{
tr_num=i+1;
tr=ptr;
}
}
if(arr[n-2-i]==1)
{
if(ptr->right==NULL)
{
return T;
}
ptr=ptr->right;
pth[i+1]=ptr;
if((ptr->flag==1 && (ptr->right!=NULL || ptr->left!=NULL)) || (ptr->right!=NULL && ptr->left!=NULL))
{
tr_num=i+1;
tr=ptr;
}
}
}
ptr->flag=0;
if(ptr->left==NULL && ptr->right==NULL)
{
for(i=n-1; i>=tr_num+1; i--)
{
delete pth[i];
pth[i]=NULL;
}
if(arr[n-tr_num-2]==1)
{
pth[tr_num]->right=NULL;
}
else if(arr[n-tr_num-2]==0)
{
pth[tr_num]->left=NULL;
}
}
return T;
}
Here's the find binary code..
int find_binary(int arr[], int num)
{
int i=0;
while(num!=0)
{
arr[i]=num%2;
num=num/2;
i++;
}
return i;
}
In another instance:
I have a function with prototype
node * search(node *T, int a);
calling this function in main
cout<<search(BT, 7);
works!
But
node *ptr=search(BT, 7);
gives segmentation error!! I am clueless why, because the similar assignment works completely fine in my delete function but in main it gives segmentation error!!
Note: node is a structure.
I compile using g++