So, I have to read a linked list from a binary file and then add new elements to it. It reads from the binary as expected, but when I try to add new elements to the list, it adds only the last one, which I enter.
Here is the code in main() responsible for reading, creating and inserting a new element into the List
int main()
{
int choice=0;
int confirmation=0;
t_Node *temp_node1, *temp_node2, *temphead;
unsigned int ID1, ID2;
FILE *fp;
fp = fopen("Data.bin","rb");
if(fp==NULL)
{
printf("File error");
exit(6);
}
while(1)
{
if(feof(fp))
{
break;
}
if (head == NULL)
{
head = readNode(fp);
temphead = head;
}else
{
temphead = readlist(temphead, fp);
}
}
fclose(fp);
while(1)
{
printf("\n\n");
printf("Hello world!\n\n 1-Enter a new element/s.\n 2-Copy data from one element to another (by ID).\n 3-Switch data between two elements (by ID).\n 4-Delete an element (by ID)\n 5-Print all elements\n 6-Delete all elements\n 0-Exit\n");
scanf("%d",&choice);
if(choice==0)
{
system("cls");
delete_List(head);
printf("EXIT BY USER");
break;
}
switch(choice)
{
case 1:
system("cls");
int temp=0;
t_Node *temphead1, *searched1, *searched2;
do
{
temphead1=makelist(temphead);
printf("press 0 to stop, any other key to go on\n");
fflush(stdin);
scanf("%d",&temp);
}while (temp!=0);
break;
case 2:
system("cls");
confirmation=0;
ID1=0;
ID2=0;
do
{
do
{
printf("Enter ID of the element you want to copy\n");
scanf("%u",&ID1);
temp_node1=Find_By_Id(ID1);
}while( temp_node1==NULL);
printNode(temp_node1);
printf("\nAre you sure?\n 1 for yes, 0 for no\n");
scanf("%d",&confirmation);
}while (confirmation==0);
confirmation=0;
do{
do{
printf("Enter ID of the element you want to copy to\n");
scanf("%u",&ID2);
temp_node2=Find_By_Id(ID2);
}while(temp_node2==NULL);
printNode(temp_node2);
printf("\nAre you sure?\n 1 for yes, 0 for no\n");
scanf("%d",&confirmation);
}while (confirmation==0);
confirmation=0;
Copy_first_to_second(temp_node1, temp_node2);
break;
case 3:
system("cls");
ID1=0;
ID2=0;
do{
do{
printf("Enter ID of the first element you want to switch data with\n");
scanf("%u",&ID1);
temp_node1=Find_By_Id(ID1);
}while( temp_node1==NULL);
printNode(temp_node1);
printf("\nAre you sure?\n 1 for Yes, 0 for No\n");
scanf("%d",&confirmation);
} while (confirmation==0);
confirmation=0;
do
{
do
{
printf("Enter ID of the second element you want to switch data with\n");
scanf("%u",&ID2);
temp_node2=Find_By_Id(ID2);
} while( temp_node2==NULL);
printNode(temp_node2);
printf("\nAre you sure?\n 1 for yes, 0 for no\n");
scanf("%d",&confirmation);
}while(confirmation==0);
confirmation=0;
Copy_first_to_second(temp_node1, temp_node2);
break;
case 4:
system("cls");
ID1=0;
do
{
do
{
printf("Enter ID of the element you want to delete\n");
scanf("%u",&ID1);
temp_node1=Find_By_Id(ID1);
} while( temp_node1==NULL);
printNode(temp_node1);
printf("\nAre you sure?\n 1 for yes, 0 for no\n");
scanf("%d",&confirmation);
}while (confirmation==0);
confirmation=0;
Delete_Element(temp_node1);
break;
case 5:
system("cls");
if (head==NULL)
{
printf("\nEnter elements first");
break;
}
printlist(head);
break;
case 6:
system("cls");
delete_List(head);
printf("List deleted");
break;
default:
delete_List(head);
exit(1);
}
}
return 0;
}
The structures:
typedef struct something
{
char name[50];
double value;
unsigned int ID;
}t_Something;
typedef struct node
{
t_Something smth;
struct node *next;
}t_Node;
And the functions:
t_Something readElement (FILE *file)
{
t_Something t_Struct;
int check=0;
unsigned int t_ID;
fread(&t_Struct,sizeof(t_Struct),1,file);
do{
t_ID=t_Struct.ID;
check=checkID(t_ID);
if (check==1)
{
break;
}
}while(1);
return t_Struct;
}
t_Something addElement()
{
t_Something t_Struct;
int check=0;
unsigned int t_ID;
printf("\nInput name\t");
fflush(stdin);
gets(t_Struct.name);
printf("\nInput value\t");
fflush(stdin);
scanf("%0.2lf",&t_Struct.value);
printf("\nInput ID, must be unique\t");
fflush(stdin);
do
{
scanf("%u",&t_Struct.ID);
t_ID=t_Struct.ID;
check=checkID(t_ID);
if (check==1)
{
break;
}
}while (1);
return t_Struct;
}
t_Node* addNode (t_Node *temphead)
{
t_Node *pNode;
pNode = (t_Node*)malloc(sizeof(t_Node));
if (pNode==NULL)
{
printf("\nMemory error\n");
delete_List(head);
}
pNode->smth=addElement();
pNode->next=NULL;
return pNode;
}
t_Node* makelist(t_Node *temphead)
{
t_Node *temp2=addNode(temphead);
temphead->next=temp2;
return temp2;
}
t_Node* readNode (FILE *file)
{
t_Node *pNode;
pNode = (t_Node*)malloc(sizeof(t_Node));
if (pNode==NULL)
{
printf("\nMemory error\n");
delete_List(head);
}
pNode->smth=readElement(file);
pNode->next=NULL;
return pNode;
}
t_Node* readlist (t_Node *temphead, FILE *file)
{
t_Node *temp2=readNode(file);
temphead->next=temp2;
return temphead->next;
}
void printlist (t_Node* current){
for (;;){
printNode(current);
current=current->next;
if (current==NULL) break;
}
}
void printNode (t_Node* current)
{
printf("\n--------\n");
printf("name: %s\n", current->smth.name);
printf("value: %lf", current->smth.value);
printf("\nID: %u\n", current->smth.ID);
}
void delete_List (t_Node* current)
{
t_Node *temp;
for (;;){
temp=current->next;
free(current);
current=temp;
if (current==NULL)
{
break;
}
}
}
int checkID (unsigned int number)
{
t_Node *current=head;
int pass=1;
if (head!=NULL)
{
for(;;)
{
if(current->smth.ID==number)
{
pass=0;
return pass;
}
current=current->next;
if (current==NULL)
{
break;
}
}
}
return pass;
}
t_Node* Find_By_Id (unsigned int searched)
{
t_Node* current=head;
for (;;)
{
if (searched==current->smth.ID)
{
return current;
}
current=current->next;
if (current==NULL)
{
break;
}
}
printf("\nThere is no element with this ID\n");
return NULL;
}
void Change_two_elements (t_Node* first, t_Node* second)
{
t_Something temp;
temp=first->smth;
first->smth=second->smth;
second->smth=temp;
}
void Copy_first_to_second (t_Node* first, t_Node* second)
{
second->smth=first->smth;
}
void Delete_Element (t_Node* element)
{
t_Node* temp;
if (element==head)
{
head=element->next;
free(element);
}else
{
for(temp=head;;)
{
if (temp->next==element)
{
break;
}
temp=temp->next;
}
temp->next=element->next;
free(element);
}
}
Sorry for the large amount of code, but otherwise it wouldn't be possible to see the full picture
