%s is skipping the entire print line - no user input

Question

What's wrong in my code? I successfully created a tree and everything is working fine except printInorder function and print statement in void main. When I try to print with %s its skipping the entire line.

Can you please help me in resolving this? I even tried fflush but it doesn't help me in my case and I don't try any scanf statement in my code.

struct Tree
{
    char data[10];
    struct Tree *left;
    struct Tree *right;
} * root;

struct Tree *createNode(char data[])
{
    struct Tree *node = malloc(sizeof(struct Tree));
    strcpy(node->data, data);
    node->left = node->right = NULL;
    insertTree(node, root, data);
}
void insertTree(struct Tree *currentNode, struct Tree *temp, char data[])
{
    char fletter=data[0];
    if (fletter=='a'||fletter=='e'||fletter=='o'||fletter=='i'||fletter=='u')
    {
        if (root == NULL)
        {
            root = currentNode;
            printf("inserted at root");
        }
        else if (temp->left == NULL)
        {
            temp->left = currentNode;
            printf("data inserted successfully at left");
        }
        else
        {
            insertTree(currentNode, temp->left,data);
        }
    }

    else
    {
         if (root == NULL)
        {
            root = currentNode;
            printf("inserted at root");
        }
        else if (temp->right == NULL)
        {
            temp->right = currentNode;
            printf("data inserted successfully at right");
        }
        else
        {
            insertTree(currentNode, temp->right,data);
        }
    }
}
void printInorder(struct Tree *tmp) 
{ 
     if (tmp == NULL) 
          return; 
     printInorder(tmp->left); 
     printf("%s ",tmp->data);   
     printInorder(tmp->right); 
} 
  

void main()
{
    struct Tree *root = createNode("saish");
    struct Tree *d1 = createNode("ansha");
    struct Tree *d2 = createNode("shish");
printf("%s",root->data);
    printInorder(root);
}

c or c++ ? Please pick one. `void main` is not valid C++, not sure about C (and thats not the only difference between the two) — 463035818_is_not_an_ai, Feb 03 '21 at 11:15
You have two *different* `root` variables. The `root` in `main` is not the same as the `root` that is used in the other functions. And your `createNode` function doesn't return anything even though it is defined to do so. — kaylum, Feb 03 '21 at 11:16
@largest_prime_is_463035818 [What should main() return in C and C++? - Stack Overflow](https://stackoverflow.com/questions/204476/what-should-main-return-in-c-and-c) — MikeCAT, Feb 03 '21 at 11:17
@MikeCAT cppref says for C "/* another implementation-defined signature */ (since C99)" (while for C++ it must return `int`). I didn't find it in the linked question wether `void` is fine in C (well, I already know that it is implementation defined) — 463035818_is_not_an_ai, Feb 03 '21 at 11:19
*both root has same pointer*. What do you mean? The `struct Tree *root` in `main` is not the same variable as the global `root` which is used in the other functions. The one in `main` has an indeterminate value because `createNode` doesn't return anything. — kaylum, Feb 03 '21 at 11:20
`createNode` is not returning anything as it should when updated with new nodes — IrAM, Feb 03 '21 at 11:21
@kaylum Thanks for helping me, Your answer works for me. Thanks for other guys too — sathish, Feb 03 '21 at 11:21
If your compiler did not shout at you for "not returning anything from a non-void function" you should turn up warnings. For GCC/clang you can do this via `-Wextra -Wall` — Gerhardh, Feb 03 '21 at 11:23
You must **never, ever** use `fflush` with `stdin`. [You should read about it](https://stackoverflow.com/questions/2979209/using-fflushstdin). — Priyanshul Govil, Feb 03 '21 at 11:41

score -1 · Accepted Answer · answered Feb 03 '21 at 11:25

createNode function doesn't return anything even though it is defined to do so.

void insertTree(struct Tree *currentNode, struct Tree *temp, char data[])
{
    char fletter=data[0];
    if (fletter=='a'||fletter=='e'||fletter=='o'||fletter=='i'||fletter=='u')
    {
        if (root == NULL)
        {
            root = currentNode;
            printf("inserted at root");
        }
        else if (temp->left == NULL)
        {
            temp->left = currentNode;
            printf("data inserted successfully at left");
        }
        else
        {
            insertTree(currentNode, temp->left,data);
return node;

        }
    }

If the problem was with `createNode`, why does this answer have redundant code for `insertTree`? — Priyanshul Govil, Feb 03 '21 at 11:35

%s is skipping the entire print line - no user input

1 Answers1