I have a problem with insertion in Binary search tree in C. I have the following definition of a binary tree(please ignore line numbers):
struct WordBT {
char *term;
struct WordBT *right;
struct WordBT *left;
};
typedef struct WordBT* WordPtrBT;
WordPtrBT mainListBT;
And my insert function:
int addlistBT(char *term, char *file, WordPtrBT curr) {
if (curr == NULL) {
WordPtrBT temp = (WordPtrBT)malloc(sizeof(WordPtrBT));
temp->term = term;
curr = temp;
return 1;
}
int test = //some test;
if (test == 0) {
return 0;
}
if (test > 0) {
addlistBT(term, file, curr->left);
}
if (test < 0) {
addlistBT(term, file, curr->right);
}
}
Then i call
addlistBT(term, file, mainListBT);
I get a seg fault later on in the program. When i debug with gdb this is what i see:
curr = temp;
(gdb) p temp
$7 = (WordPtrBT) 0x60a2a0
(gdb) p curr
$8 = (WordPtrBT) 0x0
(gdb) p mainListBT
$9 = (WordPtrBT) 0x0
(gdb) n
93 addfileBT(file, curr->file);
(gdb) p temp
$10 = (WordPtrBT) 0x60a2a0
(gdb) p curr
$11 = (WordPtrBT) 0x60a2a0
(gdb) p mainListBT
$12 = (WordPtrBT) 0x0
Now my question is that since mainListBT is defined as a pointer then why isnt mainListBT assigned the pointer to temp? Thanks
What you should do: call using addlistBT(term, file, &mainListBT); Then change the addlist function to the following:
81 int addlistBT(char *term, char *file, WordPtrBT *curr){
86 if(!(*curr)){
87 WordPtrBT temp = (WordPtrBT)malloc(sizeof(struct WordBT));
88 temp->term = term;
92 *curr = temp;
94 return 1;
95 }
96 int test = //some test;
97 if(test == 0){ return 0;}
101 if(test > 0){ addlistBT(term, file, &(*curr)->left);}
104 if(test < 0){ addlistBT(term, file, &(*curr)->right);}
107 }
some pointer magic...
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