Problem with switch C

Question

I have a C code, and without the switch, it works right, but with switch, when entering name in the list, replace all the name of the list by the same.

void insChild(LIST* l, char name[]) {
  NO* new;
  NO* p;
  p = LastChild(*l);
  new = (NO*)malloc(sizeof(NO));
  new->child = name;
  new->next = l->head;
  p->next = new;
}

Answer 1

The main problem is naming a new element in the list:

void insChild(LIST* l, char name[]) {
  ...
  NO* new;
  ...
  new = (NO*)malloc(sizeof(NO));
  new->child = name; //<---aqui

Being child a pointer, it will be pointing to the variable passed as parameter:

scanf("%s", name /*<---esta*/);

And each time you insert another node you will be pointing to the same variable name. What you want to do is actually allocate space for a new string with malloc and copy the name to that string with strcpy:

void insChild(LIST* l, char name[])
{
    ...
    NO* new;
    ...
    new = (NO*)malloc(sizeof(NO));
    new->child = malloc((strlen(name)+1)*sizeof(char));
    strcpy(new->child,name);

Note that I used the strlen to find out the size of the name and allocate a string with that size. That size had to be increased by 1 to contemplate the terminator \0 of string. All this will entail adding the reference to string.h:

#include <string.h>

Documentation for the strcpy and to the strlen

Other problems

The name problem has been solved, but there are still some things you need to get right and can improve:

• All the functions they receive LIST shall now receive LIST* because this avoids the copy of the whole structure in the call to function
• Should not use new as variable name and will bring you problems if you migrate the code to C++, because it will be a reserved word

• The Segmentation Fault which you indicated in the comments is due to the finding function of the node to be removed. Not only should the condition be changed but the pointer failed to start bef. It should be like this:

  NO* nChild(LIST *l, int n, NO** bef)
  {
      NO* p = l->head->next;
  
      //faltou aqui iniciar o ponteiro que ficava inválido não houvessem elementos
      *bef = l->head; 
      int i = 0;
  
      //ajustei aqui para n, e int del = rand() % slist; na função DelChild
      while ((p != l->head) && (i < n))  
      {
          *bef = p;
          p = p->next;
          i++;
      }
      if (i >= SizeList(l)) return NULL; //troquei a condição para facilitar
      else return p;
  }
  

View the code with all these changes working on Ideone