Thread: Help with linked list retrieval

This file will not read in the balance correctly. Could you tell me why?

Code:

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

/* Function Prototypes */
void addAccount(void);     
void listAccounts(void);				
void deleteAccount(void);				

/* The structure of a basic account */

struct account
{
	int number;
	char name[50];
	double balance;
	struct entry
	{
		int number;   /*Checkbook entry */
		int date;
		char info[100];
		union
		{
			double credit;  /*credit or debit, not both */
			double debit;
		};
	};
	struct account *next; /* Pointer to next account in linked list */
};	
struct account *firsta,*currenta,*newa; /* Linked list pointers */
int anum = 0;

int main()
{
	char c;
	firsta = NULL;
	int done = 0; /* for while loop */
	char go;		/* for exit program condition */
	while(done == 0) 
	{
		fflush(stdin);
		puts("\nDigital Checkbook\n");
		puts("A - Add new account\n");
		puts("L - List accounts\n");		/* Main menu */
		puts("D - Delete Account\n");
		puts("Q - Quit\n");
		printf("Your choice: ");
		
		c = getchar(); 
		fflush(stdin);
		c = toupper(c);
		switch(c)
		{
			case ('A'):
				addAccount();
				break;
			case ('L'):
				listAccounts();
				break;
			case ('D'):
				deleteAccount();
				break;
			case ('Q'):
				printf("\nAre you sure you want to quit? Y/N: ");
				go = getchar();
				go = toupper(go);
				if(go == 'Y')
				{
					done = 1;
					fflush(stdin);
					system("cls");
				}
				else if(go == 'N')
				{
					fflush(stdin);
					system("cls");
				}
				break;
			default:
				puts("\nInvalid answer ");
		} /*End switch*/
	} /*End while*/
	return(0);
} /*End main()*/


void addAccount(void)
{
	newa = (struct account *)malloc(sizeof(struct account)); /* Allocate proper space*/
	
	/* Check to see if this is the first record. If so, then initalize all the pointers to this first structure in the database */
	if(firsta == NULL)
	{
		firsta = currenta = newa;
	}
	
	/* Otherwise, find the end of the structure list, the one with the NULL pointer, and add on the new structure you just allocated memory for */
	
	else
	{
		currenta = firsta; 		/*make first record current */
		while(currenta->next != NULL) /*Loop through all till NULL pointer found */
		{
			currenta = currenta->next; /* last record found */
			currenta->next = newa;     /*save the address of new */
			currenta = newa; 		   /* make current record new*/
		}
	}

	/* Enter info */
	anum++;
	printf("%27s: %5i\n","Account number",anum);
	currenta->number = anum;
	printf("%27s: ","Enter account balance (Without commas)");
	scanf("%s",&currenta->balance);
	
    /* Cap new record with NULL pointer so I know it's the last record */

	currenta->next = NULL;
}

void listAccounts(void)
{
	if(firsta == NULL)
	{
		puts("There are no records to list!");
	}
	else
	{
		currenta = firsta;
		do
		{
			printf("Account number: %d\n",currenta->number);
			printf("Balance: %lf",currenta->balance);
		}
		while((currenta=currenta->next) != NULL);
	}
	getchar();
	return;
}

void deleteAccount(void)
{
}

Code:

double balance;
...
scanf("%s",&currenta->balance);

What are you doing with the call to scanf? 'balance' is type double, but you are not asking for a double with scanf....

Have you got the warnings turned on for your compiler?

Oops. Thanks a lot. It must have been a typo.

There are other problems lurking here as well.

Code:

char c;
...
c = getchar();

getchar returns an int, not a char.

Code:

fflush(stdin);

This produces undefined behaviour. See here, here, and here for an explanation.

Originally Posted by MK27

IT'S THE EXACTLY SAME THING SILLY! getchar() will never return a value higher than 127 and it exactly corresponds to the ascii value of the character, which means it's exactly the same if:

Code:

char x='x';
char x=120;

That's what getchar() does.

getchar returns a value higher than 127 quite a bit, I would guess. EOF, for one.