https://robark.gitlab.io/btree/index.htmlBinary TreesHugoen-usWed, 23 Jun 2021 23:05:30 +0000https://robark.gitlab.io/btree/intro/index.htmlTue, 22 Jun 2021 21:56:15 +0000https://robark.gitlab.io/btree/intro/index.htmlBinary Tree Introductionhttps://robark.gitlab.io/btree/traversal/index.htmlWed, 23 Jun 2021 23:05:30 +0000https://robark.gitlab.io/btree/traversal/index.htmlBinary Tree Traversal #include <queue> #include <iostream> using namespace std; struct node{ node(int x, node* l, node* r); int c; node* left; node* right; //bool operator<(conc node &rhs) conc{ // return ( c < rhs.c ); //} }; node::node(int x, node* l=0, node* r=0){ c = x; left = l; right = r; } void prewalk(node* nd){ //print, left, right cout<< nd->c <<" "; if (nd->left != 0 ) prewalk(nd->left); if (nd->right != 0 ) prewalk(nd->right); //better sol /* if (nd == 0) return; cout<< nd->c << " "; prewalk(nd->left); prewalk(nd->right); */ } void postwalk(node* nd){ //left, right, print if (nd->left != 0 ) postwalk(nd->left); if (nd->right != 0 ) postwalk(nd->right); cout<< nd->c <<" "; //better sol /* if (nd == 0) return; postwalk(nd->left); postwalk(nd->right); cout<< nd->c << " "; */ } void inwalk(node* nd){ //left, print, right if (nd->left != 0 ) inwalk(nd->left); cout<< nd->c <<" "; if (nd->right != 0 ) inwalk(nd->right); //better sol /* if (nd == 0) return; inwalk(nd->left); cout<< nd->c << " "; inwalk(nd->right); */ } void bfirstwalk(node* root){ queue <node*> q; node* n; q.push(root); while ( !q.empty() ) { n = q.front(); cout << n->c <<" "; if ( n->left != 0 ) q.push(n->left); if ( n->right != 0 ) q.push(n->right); q.pop(); } cout<<endl; } //alternate method which pushes null nodes /* void bfirstwalk(node* root){ queue <node*> q; node* n; q.push(root); while ( !q.empty() ) { if (q.front() != 0) { n = q.front(); cout << n->c <<","; q.push(n->left); q.push(n->right); } q.pop(); } cout<<endl; } */ /* node* NewNode(int c){ node* np = new node; np->c = c; np->left = 0; np->right = 0; return np; } */ /* must pass nd by ref since we may need to insert at the root node if tree is empty and hence change the root addr */ void insert(node* &nd, int c){ if (nd == 0) { //nd = NewNode(c); nd = new node(c); return; } if (c < nd->c) { insert(nd->left, c); } else { insert(nd->right, c); } } void btfree(node* nd){ //must be post order for deleting (fails if root=0) if (nd->left != 0) btfree(nd->left); if (nd->right != 0) btfree(nd->right); delete nd; nd = 0; //better sol /* if (nd == 0) return; btfree(nd->left); btfree(nd->right); delete nd; nd = 0; */ } //alternate better solution (check after instead of before) /* void btfree(node* nd){ //must be post order for deleting if (nd !=0) //same as if (nd) { btfree(nd->left); btfree(nd->right); delete nd; nd = 0; } } */ int main(){ const int iarray[7] = {4,2,6,1,3,5,7}; node* root=0; int x; for (x=0; x < 7 ; x++) { insert(root, iarray[x]); //walk(root); //cout<<endl; } cout<<"prewalk "; prewalk(root); cout<<endl; cout<<"postwalk "; postwalk(root); cout<<endl; cout<<"inwalk "; inwalk(root); cout<<endl; cout<<"bfirstwalk "; bfirstwalk(root); cout<<endl; btfree(root); return (0); }