An issue with displaying function in C/C++

[NoWeDoR]

Hello guys.

I want to create a simply circular linked list that shows the entered names on the screen.

I also created it but I guess there is something wrong in displayList() function. When I run the codes (which are I've shared below), it shows me strange symbols, articles etc. Would you run and help me about the problem?


#include <stdio.h>#include <stdlib.h>


struct list
{
char *data;
struct list *next;
};


typedef struct list List;
typedef List *ptrList;
ptrList head;


void createALinkedList()
{
int i, elementNumber;
char value[25];
printf("Express that how many name you'll enter: ");
scanf_s("%d", &elementNumber);
for (i = 0; i < elementNumber; i++)
{
printf("Enter %d. name of list: ", i + 1);
scanf("%s", &value);
if (head == NULL)
{
head = (List *)malloc(sizeof(List));
head->data = value;
head->next = head;
}
else
{
ptrList temp1 = head;
ptrList temp2 = (List *)malloc(sizeof(List));
while (temp1->next != head)
{
temp1 = temp1->next;
}
temp1->next = temp2;
temp2->data = value;
temp2->next = head;
}
}
}


void displayList()
{
ptrList temp = head;
do
{
printf("%s\n", temp->data);
temp = temp->next;
} while (temp != head);
}




int main()
{
createALinkedList();


printf("\n*-* First statement of list *-*\n");
displayList();


return 0;
}

[steeldriver]

Your



head->data = value;


just assigns the value of the local pointer: you need to allocate explicit storage for each data string within each struct member that you create, and then strcpy or strncpy the respective `value`s to them, I think. Don't forget to `free` the memory at the end.

[spjackson]

You don't allocate any memory for the data. Here's one way to do it


head->data = strdup(value);
temp2->data = strdup(value);