c++ - double free or corruption when implement binary tree -

update:

add more code asked.pasted end of question. stops.

current code fine delete leaf, come root, can not delete.

==== update: revise code, change removerootmatch to

tmp = root; root = tmp->right;  tmp->right = null; delete tmp; 

and no error not delete node.

=====

the program simple following step:

• find min value of binary tree;
• record min value in vector;
• delete node min value in tree;
• repeat 1-3 till tree empty.

i have removenode()function, call removeroot function(check code below),if 1 needed removed root. have trouble function. doing debug , found wrong removerootmatch function. give error when run. error got error got *** glibc detected *** ./bintree: double free or corruption (fasttop): 0x0000000000727060 ***, 1 can me?

the tree defined following, language c++

typedef struct mynode* lpnode; typedef struct mynode node; struct mynode {   double key;    lpnode left; //left subtree   lpnode right; //right subtree }; 

main part of program following:

• nmax initialed 0,
• sortedvector alloacted vector space large total nodes in tree,
• min initialed 99999.
• minvalue return min value of tree.
• comparedouble(a,b) return 1 if < b,return 2 if > b,return 3 if equal

code following

    void removerootmatch(lpnode root) {     lpnode tmp = makenewnode(root->key);     tmp->left = root->left;     tmp->right = root->right;     //no child     if(root->left==null && root->right == null) {          root=null;     delete root;     } else if(root->left==null && root->right!=null){ //one right child         //delete root;             root = tmp->right;         tmp->right = null;         delete tmp;     } else {         printf("remove root bug!\n");     } } 

this function call removenode function.

//compare double int comparedouble(double a,double b) {     if(a-b<-epsilon) //a<b         return 1;     else if(a-b>epsilon)//a>b         return 2;     else         return 3; }   //find min key in tree double minvalue(lpnode root,double min)  {     if(root == null)         return min;     if(comparedouble(root->key,min)==1)         min = root->key;     min = minvalue(root->left, min);     min = minvalue(root->right, min);     return min; }  //remove root void removerootmatch(lpnode& root) {     lpnode tmp = makenewnode(root->key);     tmp->left = root->left;     tmp->right = root->right;     //no child     if(root->left==null && root->right == null) {         root=null;         delete root;     } else if(root->left==null && root->right!=null){ //one right child          double k = root->key;           root = tmp->right;         tmp->right = null;         delete tmp;         //tmp=tmp->right;         //root->right = null;         //delete root;         //root = tmp;          } else {         printf("remove root bug!\n");     } }  //remove node void removematch(lpnode& root,lpnode match,bool left) {     //no child     if(match->left==null && match->right == null){         double k = match->key;         left==true?         root->left=null:         root->right=null;         delete match;         if(!root->left)printf("%f  ",k);     }     else if(match->left==null && match->right!=null){//one right child                 double k = match->key;          left==true?         root->left=match->right:         root->right=match->right;         delete match;         if(!root->left)printf("%f  ",k);     } else {         printf("remove root bug!\n");     } }   //delete node void removenode(lpnode root,double min) {     if(comparedouble(min,root->key)==3){         removerootmatch(root);     }else if(comparedouble(min,root->key)==1 && root->left != null) {          comparedouble(min,root->left->key)==3 ?         removematch(root,root->left,true):         removenode(root->left,min);     }else if(comparedouble(min,root->key)==2 && root->right != null){          comparedouble(min,root->right->key)==3 ?         removematch(root,root->right,false):         removenode(root->right,min);     }else{         printf("remove bug1!\n");     } }  //call minvalue find min key //record min key in vector //call removenode delete node //repeat till tree empty void problem1(lpnode root,double* sortedvector,int& nmax) {            double min;     //while(root!=null)     for(int i=0;i<3;i++)     {         min = max;         sortedvector[nmax] = minvalue(root,min) ;         printf("inv%f\n",sortedvector[nmax]);         removenode(root,sortedvector[nmax]);         nmax++;     }     printf("the tree empty"); } 

if function removenode may adjust root, function not declared properly.

 void removerootmatch(lpnode root) 

you passing pointer root. inside removerootmatch function, working on copy of pointer. code inside of removerootmatch function:

root = tmp->right;     tmp->right = null;     delete tmp; 

does not change root node when function returns.

to address issue, should pass root pointer reference:

 void removerootmatch(lpnode& root)