C Segmentation fault function reference [closed] - c

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The if(ptr->is_word) on the sizeH(node *ptr) function is causing a segmentation fault.
dictionary.c:120:13: runtime error: member access within null pointer of type 'node' (aka 'struct node')
dictionary.c:120:13: runtime error: load of null pointer of type '_Bool'
Segmentation fault
If I add an if condition to return a specific value before this if-condition, the code executes and I make sure the root isn't null
so I guess the problem is the ptr isn't passed correctly to the sizeH function.
unsigned int size(void)
{
node *ptr = root;
printf(ptr->is_word ? "true" : "false");
unsigned int count = sizeH(ptr);
printf("COUNTER IN SIZE %d\n" , count);
return 0;
}
unsigned int sizeH(node *ptr){
if(ptr->is_word)
{
return 1;
}
else
{
for(int x = 0; x < N; x++){
return 0 + sizeH(ptr->children[x]);
}
}
return 0;
}

Answer 1

There's a couple of fundamental problems with your sizeH function. Firstly it doesn't check that the ptr that is passed in is not NULL. This is very likely to happen as your function is recursive and you have this loop that is called for each child node.
for(int x = 0; x < N; x++){
return 0 + sizeH(ptr->children[x]);
}
Except that the code in the loop is wrong and it'll only ever be called for the first child, which is the second issue. Because you use return inside the loop, it'll only ever run once. Instead you should tally up the values returned for each child node and then return that.
Making the two changes above would leave your function looking like this.
unsigned int sizeH(node *ptr) {
if(ptr==NULL) {
return 0;
} else if(ptr->is_word) {
return 1;
} else {
unsigned int ret = 0;
for(int x = 0; x < N; x++) {
ret += sizeH(ptr->children[x]);
}
return ret;
}
// return 0; This isn't needed - the code will never reach here.
}
It's also worth picking one coding formatting style and sticking to it rather than using a mixture as it makes for neater code.