Thread: Using a linked list globally and File I/O

I assume the number in the list to delete. X numbers from head. That's what I gather from the code.

Deleting the first person on the list works fine, because we never enter the loop anyway, so it doesn't matter.

Here's the full code along with the process that calls it so that you can fully understand how it works.

Code:

void search(struct node** head, int afunc)
/* afunc: 0 = delete, 1 = print */
{
	int choice;
	long int aa;
	char lastname[20];
	int count = 0;
	struct node* current = *head;
	
	printf("\nAnazhthsh vash se:\n\n");
	printf("1. ASM\n");
	printf("2. Epitheto\n\n");
	printf("Epilogh: ");
	fflush(stdin);
	scanf("%1d", &choice);
	
	switch(choice)
	{
		case 1:
		printf("\nDwse ASM: ");
		scanf("%6ld", &aa);
		while (current != NULL && current->soldier.aa != 0) {
			count++;
			if (aa == current->soldier.aa) {
				if (afunc == 1) {
					printone(&current, 0);
					printf("\n");
					fflush(stdin);
					getchar();
					return;
				}
				else goto delrecbreak;
			}
			current = current->next;
		}
		printf("Den vrethike o ASM pou dwsate.\n");
		case 2:
		printf("\nDwse epitheto: ");
		fflush(stdin);
		fgets(lastname, 20, stdin);
		lastname[strlen(lastname)-1] = '\0';
		while (current != NULL && current->soldier.aa != 0) {
			count++;
			if (strcmp(lastname, current->soldier.lastname) == 0) {
				if (afunc == 1) {
					printone(&current, 0);
					printf("\n");
					fflush(stdin);
					getchar();
					return;
				}
				else goto delrecbreak;
			}
			current = current->next;
		}
		printf("Den vrethike stratiwths me to epitheto pou dwsate.\n");
	}
	delrecbreak:
	if (afunc == 0) delrec(&*head, count);
}

void delrec(struct node** head, int acount)
{
	int i;
	struct node* current = *head;
	struct node* previous = NULL;
	
	for (i=1;i<=acount-1;i++)
	{
		previous = current;
		current = current->next;
	}
	
	if (previous == NULL) *head = current->next;
	else previous->next = current->next;
	free(current);
}

And because I bet you don't really understand greeklish, what search() does is ask the user if he wants to search for a certain soldier via index or their surname, and depending on afunc (whether the user selected "search and delete" or "search and print" in the main menu), search prints the current soldier or passes their linked list "index" to delrec(), which goes to delete that record.

http://faq.cprogramming.com/cgi-bin/...&id=1043284351

yeah I'm not getting this. Could you post the whole program?

and is this for a homework assignment? do you have to use those function prototypes?

For arrays - just don't go over bounds. No matter how many idexes you create in there, there's always a chance you'll do out of bounds, so do proper checking first.
And for second, you can use fgets and you don't have to worry about the input buffer at all, which is the preferred solution.

fgets reads everything into the buffer and does not leave dangling newlines in the input buffer.
You don't like the newline? You can get rid of it by erasing the last element in a string array.

I'm already doing that, by insterting \0 in strlen-1. Let me check which function keeps the \n and I'll get back and edit.

EDIT: Found it. fgets following scanf is overriden.

Code:

	printf("\n");
	printf("Dwse ASM stratiwth (6 pshfia): ");
	scanf("%6ld", &soldiers.aa);
	
	printf("Dwse onoma stratiwth: ");
	fgets(soldiers.firstname, 20, stdin);
	soldiers.firstname[strlen(soldiers.firstname)-1] = '\0';

The fgets doesn't give me a chance to input at all.

use fgets for ALL input
and than parse it with something like sscanf

http://faq.cprogramming.com/cgi-bin/...&id=1043284385

see OPTION 3 Read As A String and Convert

I'm getting annoyed with the newline problem. If anyone could provide a solution, please do so. Here's the code.

Code:

int main(int argc, char *argv[])
{
	int choice;
	char choice2[3];
	
	/* if (argc!=2) {
	printf("Usage: SOLDIERSDB <database>\n");
	exit(1);
	}
	
	struct node* head = loadfile(*argv[1]); */
	struct node* head = loadfile("soldiers");

	for(;;)
	{
		choice = menu();
		switch(choice)
		{
			case 1:	create(&head); continue;
			case 2:	search(&head, 0); continue;
			case 3:	search(&head, 1); continue;
			case 4:	printall(&head); continue;
			case 5:	printf("5 not completed.");	continue;
			case 6:	printf("6 not completed.");	continue;
			case 7:	savedb(head, "soldiers"); continue;
			/* Exit */
			case 8:
			printf("\nAll unsaved changes will be lost. Are you sure you want");
			printf("\nto exit?\n");
			fgets(choice2, 3, stdin);
			choice2[strlen(choice2)-1] = '\0';
			if (choice2=="y") break;
			else continue;
			/* Not a valid menu selection */
			default:
			continue;
		}
		break;
	}
	return 0;
}

int menu()
{
	int choice;
	
	printf("\nDialekste epilogh:\n\n");
	printf("1. Eisagwgh stratiwth\n");
	printf("2. Diagrafh stratiwth\n");
	printf("3. Ektypwsh stratiwth\n");
	printf("4. Ektypwsh olwn\n");
	printf("5. Epilogh twn N prwtwn stratiwtwn pou exoun dikaiwma na\n");
	printf("   paroun M meres adeia.\n");
	printf("6. Epilogh twn N prwtwn stratiwtwn gia yphresia\n");
	printf("7. Apo8hkeysh vashs dedomenwn.\n");
	printf("8. Exodos.\n");
	printf("\nEpilogh: ");
	
	fgets(tempbuf, 3, stdin);
	choice = atoi(tempbuf);	
	return choice;
}

Never mind the greeklish. I choose option 8 at the menu, but then even if I type y at the prompt to exit, the program just displays the menu again.

EDIT: This works:

Code:

fgets(choice2, 3, stdin);
choice2[strlen(choice2)-1] = '\0';
if (choice2[0]=='y' && choice2[1]=='\0') break;