Use Recursive Algorithms and non-recursive algorithms to traverse Binary Trees

Recursive Algorithm:

# Include <iostream. h>
Typedef char elemtype;
Struct bitree
{
Elemtype data;
Bitree * lchild, * rchild;

};
Bitree * Create () // create a binary linked list
{
Bitree * Q [100]; // defines the Q array as the queue for storing nodes in the binary linked list. 100 is the maximum capacity.
Bitree * s; // node of the binary linked list
Bitree * root; // binary linked list root pointer
Int front = 1, rear = 0; // define the header and tail pointer
Char ch; // The data field of the node
Root = NULL;
Cout <"Enter the node value (the nonexistent value is ','; '#' indicates the end )";
Cin> CH;
While (Ch! = '#') // Until input # ends with the algorithm
{
S = NULL;
If (Ch! = ',') // "," Indicates a virtual node
{
S = new bitree;
S-> DATA = CH;
S-> lchild = NULL;
S-> rchild = NULL;
}
Rear ++;
Q [rear] = s;
If (Rear = 1) root = s;
Else
{
If (S! = NULL) & (Q [Front]! = NULL ))
{
If (Rear % 2 = 0) Q [Front]-> lchild = s; // rear is an even number, and s is the left child
Else Q [Front]-> rchild = s; // The rear is an odd number, and the S is the right child.
}
If (Rear % 2 = 1) Front ++; // leaves
}
Cin> CH;
}
Return root;
}

Void preorder (bitree * root) // preorder traversal
{
Bitree * P;
P = root;
If (P! = NULL)
{
Cout <p-> data <Endl;
Preorder (p-> lchild );
Preorder (p-> rchild );
}
}
Void inorder (bitree * root) // supports sequential traversal.
{
Bitree * P;
P = root;
If (P! = NULL)
{
Inorder (p-> lchild );
Cout <p-> data <Endl;
Inorder (p-> rchild );
}
}
Void postorder (bitree * root) // post-order traversal
{
Bitree * P;
P = root;
If (P! = NULL)
{
Postorder (p-> lchild );
Postorder (p-> rchild );
Cout <p-> data <Endl;
}
}

Void main ()
{
Bitree * root;
Root = create ();
Cout <Endl <"returns the traversal result before the left and right subtree is exchanged:" <Endl;
Cout <"sequential traversal" <Endl;
Preorder (Root); cout <Endl;
Cout <"sequential traversal" <Endl;
Inorder (Root); cout <Endl;
Cout <"post-order traversal" <Endl;
Postorder (Root); cout <Endl;

}

Non-recursive algorithms: stacks must be set in non-recursive algorithms.

# Include <iostream. h>
Typedef char elemtype;
Struct bitree
{
Elemtype data;
Bitree * lchild, * rchild;

};
Bitree * Create () // create a binary linked list
{
Bitree * Q [100]; // defines the Q array as the queue for storing nodes in the binary linked list. 100 is the maximum capacity.
Bitree * s; // node of the binary linked list
Bitree * root; // binary linked list root pointer
Int front = 1, rear = 0; // define the header and tail pointer
Char ch; // The data field of the node
Root = NULL;
Cout <"Enter the node value (the nonexistent value is ','; '#' indicates the end )";
Cin> CH;
While (Ch! = '#') // Until input # ends with the algorithm
{
S = NULL;
If (Ch! = ',') // "," Indicates a virtual node
{
S = new bitree;
S-> DATA = CH;
S-> lchild = NULL;
S-> rchild = NULL;
}
Rear ++;
Q [rear] = s;
If (Rear = 1) root = s;
Else
{
If (S! = NULL) & (Q [Front]! = NULL ))
{
If (Rear % 2 = 0) Q [Front]-> lchild = s; // rear is an even number, and s is the left child
Else Q [Front]-> rchild = s; // The rear is an odd number, and the S is the right child.
}
If (Rear % 2 = 1) Front ++; // leaves
}
Cin> CH;
}
Return root;
}

Void preorder (bitree * root) // preorder traversal
{
Bitree * P, * s [100];
Int Top = 0;
P = root;
While (P! = NULL) | (top> 0 ))
{
While (P! = NULL)
{
Cout <p-> data <"";
S [++ top] = P;
P = p-> lchild;
}
P = s [top --];
P = p-> rchild;
}
}
Void inorder (bitree * root) // supports sequential traversal.
{
Bitree * P, * s [100];
Int Top = 0;
P = root;
While (P! = NULL) | (top> 0 ))
{
While (P! = NULL)
{
S [++ top] = P;
P = p-> lchild;
}
{
P = s [top --];
Cout <p-> data;
P = p-> rchild;
}
}
}
Void postorder (bitree * root) // post-order traversal
{
Bitree * P, * s [100];
Int S2 [100], Top = 0, B;
P = root;
Do
{
While (P! = NULL)
{
S [Top] = P; S2 [top ++] = 0;
P = p-> lchild;
}
If (top> 0)
{
B = S2 [-- top];
P = s [Top];
If (B = 0)
{
S [Top] = P;
S2 [top ++] = 1;
P = p-> rchild;
}
Else
{
Cout <p-> data <"";
P = NULL;
}
}
}
While (top> 0 );
}

Void main ()
{
Bitree * root;
Root = create ();
Cout <Endl <"returns the traversal result before the left and right subtree is exchanged:" <Endl;
Cout <"sequential traversal" <Endl;
Preorder (Root); cout <Endl;
Cout <"sequential traversal" <Endl;
Inorder (Root); cout <Endl;
Cout <"post-order traversal" <Endl;
Postorder (Root); cout <Endl;

}