Struct listing , member delete - c

Question

i'm a freshman computer engineering student. When i preparing an program to store students' info in a C program, some problems appeared.
screen : http://imgim.com/5025incii2829330.jpg
I've added two students and deleted first student's info. But first student's info still appears as empty.
here's the code : http://pastebin.com/R6rSXaft

Answer 1

In your orgListele function, you are iterating through an array of students in order to print out the information. Your for loop prints information like so:
for (i = 0; i<sayi; i++)
{
printf("\n\nStudent:%d\n", i + 1);
printf("ID:%s\n ", listeler[i].id);
printf("National ID:%s\n", listeler[i].tckimlik);
printf("Name:%s\n", listeler[i].isim);
printf("Address:%s\n", listeler[i].adres);
printf("Phone Number:%s\n", listeler[i].telefonnum);
}
It looks like you are not really deleting students from the array (not possible, anyways), just clearing their information. You have created the list of liste structures as an array rather than a list with variable size. When you iterate through it, you are printing the students, even if their information has been cleared.
To achieve the output that you want, I would do one of two things:
Use a linked list and delete the nodes that you want. When you traverse the list to print everything out, you will not be using deleted nodes because they are not referenced by your list any more. The array implementation does not offer this "deletion" aspect. It will also allow this application to scale past 30 students (which is a limitation posed by your array, declared as struct liste listeler[30];. This is the approach I would take. See here for some information on linked lists.
Add another flag to your liste struct to maintain deletion state. If you add something that acts as a boolean value, say int isValid, you will be able to clear that variable (make it 0) for the next time you run through the loop. Then, you can say if (listeler[i].isValid) {//print everything} and skip over those students who have been marked as invalid (isValid = 0)

Answer 2

change
for (i = 0; i<sayi; i++) //kayit sayisi degismediginden
{
printf("\n\nStudent:%d\n", i + 1);
printf("ID:%s\n ", listeler[i].id);
printf("National ID:%s\n", listeler[i].tckimlik);
printf("Name:%s\n", listeler[i].isim);
printf("Address:%s\n", listeler[i].adres);
printf("Phone Number:%s\n", listeler[i].telefonnum);
}
to
for (i = 0; i<sayi; i++) //kayit sayisi degismediginden
{
if(listeler[i].id == 0) contnue; // skip the element if id is zero (zero idicates deleted item)
printf("\n\nStudent:%d\n", i + 1);
printf("ID:%s\n ", listeler[i].id);
printf("National ID:%s\n", listeler[i].tckimlik);
printf("Name:%s\n", listeler[i].isim);
printf("Address:%s\n", listeler[i].adres);
printf("Phone Number:%s\n", listeler[i].telefonnum);
}

Answer 3

You don't keep track of which structures are "empty" or not, you always print all up to the limit imposed by the sayi global variable.
The simple solution is to skip printing those with an empty id, for example, or some other field.

Answer 4

Setting the variable's value to NULL doesn't delete the variable... It simply makes it null. Consider looking into dynamic memory allocation, and using the free() method when you want to delete a student, which has been malloced.

Answer 5

You have removed the information about the student, but you have not deleted the record. You need to delete the record and adjust the list (listeler) so that there are no empty entries within the entries contained.