How to delete a word from tree dictionnary in C? - c

Question

I've implemented a dictionnary in C using tree, this tree stores a word and its definition as followed:
As you can see, some words are sharing same letters.
But now i'd like to implement a delete function but don't know how to proceed ... I know that I should begin to delete the end of the word ...
Here is my code, thank you for your future help !
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct _noeud{
char *value;
struct _noeud *child[26];
}noeud_t;
typedef struct tree{
node_t root;
}Tree;
Tree dict;
int getPos(char letter){
char alpha[26]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
int i;
for(i=0;i<strlen(alpha);i++){
if(alpha[i]==letter){
return i;
}
}
return -1;
}
void addWord(node_t *node, char *word, char *def){
int i;
for(i = 0; i < strlen(word);i++){
int letter=getPos(word[i]);
if(letter==-1){
printf("Unknown letter... \n");
}
node_t *parent = node;
node = node->child[letter];
if(!node){
node = malloc(sizeof(node_t));
parent->child[letter]=node;
}
}
node->value = malloc(strlen(def)+1);
strncpy(node->value,def,strlen(def)),
printf("Word %s added to dictionnary.\n",word);
fflush(stdin);
}
void findWord(node_t *node, char *word){
printf("Looking for word %s \n",word);
int i;
for(i=0;i<strlen(word);i++) {
int letter = getPos(word[i]);
if(NULL ==node->child[letter]){
printf("Unknown word ...\n");
return;
}
else{
node = node->child[letter];
}
}
printf("Word found, its definition is : %s\n",node->value);
}
void deleteWord(node_t *node, char *word){
int i=0;
for(i=0;i<strlen(word);i++) {
//...
}
printf("Word deleted !\n");
}
int main(){
addWord(&dico.root,"dog","it's an animal");
addWord(&dico.root,"pineapple","it's a fruit");
addWord(&dico.root,"car","something to drive");
findWord(&dico.root,"dog");
findWord(&dico.root,"car");
findWord(&dico.root,"pineapple");
deleteWord(&dico.root,"pineapple");
return 0;
}

Answer 1

I can give you an idea on how to solve it, but sorry I didn’t write the code.
So from your code, I can see that you have findWord function, if that works perfectly then use it inside your delete go find the word at this stage you’re pointing to it now you have to think of three possibilities.
If the word that will be deleted doesn’t have any child then delete it with no more complication.
If the word that will be deleted has a single child then make the parent of the word point to the word’s child.
If the word that will be deleted has more than one child then replace the word with one of the children and then delete it.
I hope this will help you