CODEWITHSUNDEEP
c++binary-treebreadth-first-search
Who Cares
Who Cares

Reputation: 205

Breadth First Search on a Binary tree

I'm trying to traverse on a binary tree to find someone's ID by using his/her ID number. When I debug this function it works well, but on the other hand, when I directly run, it terminates itself.. Can someone figure it out please?

struct person{
char ID[15];
char name[30] ;
char surname[30];
person *left;
person *right;
};

struct tree{
person *root;
void bfsSearch();
void BFS(person*,char*);
};

void tree::BFS(person *root,char *search)
//BFS traversal on a binary tree
{
    char *temp;
    std::deque<person *> q;
    q.push_back(root);
temp=strncpy(temp,q.front()->ID,8);
while (q.size() != 0)
{
    person *next = q.front();

    if (strcmp(search,temp)==0)
    {
      cout<<"Result: "<<q.front()->ID<<endl;
      break;
    }
    q.pop_front();

    if (next->left)
        q.push_back(next->sol);
    if (next->right)
        q.push_back(next->sag);
    temp=strncpy(temp,q.front()->ID,8);
    }
}

void tree::bfsSearch()
{
    person *scan;
    char *data,*temp;
    data=new char[15];
    scan=root;
    cout<<"Enter the Person`s ID to search: ";cin>>data;
    BFS(root,data);

}

Upvotes: 2

Views: 2771

Answers (1)

interjay
interjay

Reputation: 110108

char *temp;
temp=strncpy(temp,q.front()->ID,8);

You are copying data into an uninitialized pointer, which is undefined behavior. You need to declare temp as an array, or allocate it dynamically. Since you are only copying up to 8 bytes, using char temp[9]; should be enough. Note though that strncpy will leave the string unterminated if the input was too long, so you'd need to add temp[8]=0; to be safe.

There is also no point in assigning the result of strncpy back to temp, since it just returns its first argument.

It's much better to do things the C++ way: Use std::string and avoid all this messing around with char pointers and null-terminators.

Upvotes: 1

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