Okay, so my program is very close to completion. The only problem is that the program leaks memory. The deleteNode, deleteManager, and destroyList are the ones to blame, or so I think. When I delete a node other than the first one it works while leaking memory. However, when I try deleting the first node and then try to display the list again, the program crashes. Perhaps my deleteNode function needs some readjustment. In any case, here is the code and the input file.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#include<crtdbg.h>
#define FLUSH while (getchar () != '\n')
#define FILE_IN "countries.txt"
// Type Definitions
typedef char KEY_TYPE;
typedef struct {
char *name;
char *capital;
long population;
} COUNTRY;
typedef struct {
KEY_TYPE key[3];
COUNTRY list;
} DATA;
typedef struct nodeTag {
DATA data;
struct nodeTag* link;
} NODE;
// Prototype Declarations
char getOption (void);
void printMenu (void);
int searchList (NODE *pList, NODE **pPre, NODE **pCur, char target[]);
NODE *insertNode (NODE *pList, NODE *pPre, DATA item);
NODE *deleteNode (NODE *pList, NODE *pPre, NODE *pCur);
void printList (NODE *pList);
NODE *destroyList (NODE *pList);
NODE *buildList (void);
NODE *processListManager (NODE *pList);
void searchManager (NODE *pList);
NODE *insertManager (NODE *pList);
NODE *deleteManager (NODE *pList);
int getData ( FILE *spIn, DATA *data );
void insertCommas ( NODE *pWalker, char *population );
void printCountry ( NODE *list, char populationInCommas[] );
int insertHandler ( DATA *data, char target[] );
int main ( void )
{
// Local Definitions
NODE *list = NULL;
// Statements
printf("\t\t LAB 8 - LINKED LISTS\n\n");
list = buildList();
printMenu();
processListManager ( list );
list = destroyList ( list );
printf("\n\t\tEnd of LAB 8 - LINKED LISTS"
"\n\t\tHave a great day!\n");
printf( _CrtDumpMemoryLeaks() ? "Memory Leak\n" : "No Leak\n");
return 0;
}// main
/* ==================== getOption ====================
Gets and validates the user's option.
Pre : nothing
Post : valid option returned
*/
char getOption (void)
{
// Local Definitions
char option;
// Statements
printf ("\n\nPlease enter the option: ");
scanf ("%c", &option);
FLUSH;
option = toupper (option);
while(strchr("LSIDME", option) == NULL)
{
printf("\a*** Invalid option! ***\n");
printf("Enter one of the following letters: L, S, I, D, M, E: " );
scanf ("%c", &option);
FLUSH;
option = toupper (option);
}
return option;
} // getOption
/* ============================== printMenu ==============================
Prints the menu to the screen.
PRE : nothing
POST : menu printed
*/
void printMenu (void)
{
// Local Definitions
// Statements
printf("\n\t\t**********************"
"\n\t\t* *"
"\n\t\t* L - List *"
"\n\t\t* S - Search *"
"\n\t\t* I - Insert *"
"\n\t\t* D - Delete *"
"\n\t\t* M - Print Menu *"
"\n\t\t* E - Exit *"
"\n\t\t* *"
"\n\t\t**********************");
return;
} // printMenu
/* ============================== processListManager ====================
Process user's option by calling appropriate functions.
PRE : pList - a pointer to the first node of a linked list
POST : pList - might be changed after inserting or deleting
*/
NODE *processListManager (NODE *pList)
{
// Local Definitions
char option;
// Statements
do
{
option = getOption();
switch(option)
{
case 'L' : printList (pList);
break;
case 'S' : searchManager (pList);
break;
case 'I' : pList = insertManager (pList);
break;
case 'D' : pList = deleteManager (pList);
break;
case 'M' : printMenu ();
break;
case 'E' : printf("End of processing!\n");
break;
default : break;
}
} while (option != 'E');
return pList;
} // processListManager
NODE *buildList (void)
{
// Local Declarations
NODE *pList;
NODE *pPre;
NODE *pCur;
DATA data;
FILE *spIn;
int result;
// Statements
if ( ! ( spIn = fopen ( FILE_IN, "r" ) ) ) {
printf("Error opening file %s\n", FILE_IN);
exit(100);
}
pList = NULL;
while ( getData ( spIn, &data ) ) {
result = searchList(pList, &pPre, &pCur, data.key);
if ( !result )
pList = insertNode(pList, pPre, data);
}
fclose ( spIn );
return pList;
} // buildList
int getData ( FILE *spIn, DATA *data )
{
// Local Declarations
int result;
// Statements
data->list.name = (char*)calloc(21, sizeof(char));
data->list.capital = (char*)calloc(16, sizeof(char));
result = fscanf ( spIn, "%2s %20[^;] %*c %15[^;] %*c %ld",
data->key, data->list.name,
data->list.capital, &(data->list.population) );
if ( result == 4 )
return 1;
else {
free ( data->list.name );
free ( data->list.capital );
return 0;
}
} // getData
NODE *insertNode (NODE *pList, NODE *pPre, DATA item)
{
// Local Declarations
NODE *pNew;
// Statements
if ( ! ( pNew = (NODE*)malloc(sizeof(NODE))))
printf("Memory is unavailable.\n"),
exit(200);
pNew->data = item;
if ( pPre == NULL ) {
pNew->link = pList;
pList = pNew;
}
else {
pNew->link = pPre->link;
pPre->link = pNew;
}
return pList;
} // insertNode
int searchList (NODE *pList, NODE **pPre, NODE **pCur, char target[])
{
// Local Declarations
int found = 0;
// Statements
*pPre = NULL;
*pCur = pList;
while (*pCur != NULL) {
if (strcmp ( target, (*pCur)->data.key) == 0 ){
found = 1;
break;
}
*pPre = *pCur;
*pCur = (*pCur)->link;
}
return found;
} // searchList
void printList (NODE *pList)
{
// Local Declarations
NODE *pWalker;
// Statements
printf( "== ====================\n"
"ID NAME \n"
"== ====================\n");
pWalker = pList;
while ( pWalker ) {
printf("%s %-20s\n",
pWalker->data.key, pWalker->data.list.name);
pWalker = pWalker->link;
}
printf( "=======================" );
return;
} // printList
void insertCommas ( NODE *pWalker, char *population )
{
// Local Declarations
char printString[15];
char tempString[15];
char insertComma[] = ",";
int strLength;
int checkRmdr;
int i;
// Statements
*printString = '\0';
sprintf(tempString, "%ld", pWalker->data.list.population);
strLength = strlen ( tempString );
checkRmdr = strLength % 3;
if ( checkRmdr > 0 ) {
strncat ( printString, tempString, checkRmdr );
strcat ( printString, insertComma );
}
for ( i = checkRmdr; i < (int) strlen ( tempString ); ) {
strncat ( printString, tempString + i, 3 );
i += 3;
strcat ( printString, insertComma );
}
printString[strlen(printString) - 1] = '\0';
strcpy (population, printString);
return;
} // insertCommas
void searchManager (NODE *pList)
{
// Local Declarations
NODE *pPre;
NODE *pCur;
char target[3];
char populationInCommas[15];
// Statements
printf("Please enter a key: ");
scanf("%2s", target);
FLUSH;
if ( searchList ( pList, &pPre, &pCur, target ) ) {
insertCommas(pCur, populationInCommas);
printCountry(pCur, populationInCommas);
}
else
printf("Country could not be found. Please try again.");
return;
} // searchManager
void printCountry ( NODE *list, char populationInCommas[] )
{
// Statements
printf( "\n ID: %s\n"
" Name: %s\n"
" Capital: %s\n"
"Population: %s\n", list->data.key,
list->data.list.name,
list->data.list.capital,
populationInCommas);
} // printCountry
NODE *insertManager (NODE *pList)
{
// Local Declarations
NODE *pPre;
NODE *pCur;
DATA insertData;
int position;
char target[3];
int counter = 1;
// Statements
printf("Please enter a key: ");
scanf("%2s", target);
FLUSH;
if ( ! ( searchList ( pList, &pPre, &pCur, target ) ) ) {
position = insertHandler ( &insertData, target );
switch (position) {
case 1: pPre = NULL;
break;
case 2: pPre = pList;
while (pPre) {
pPre = pPre->link;
counter++;
}
counter /= 2;
pPre = pList;
while ( counter != 1 ) {
pPre = pPre->link;
counter--;
}
break;
case 3: pPre->link = NULL;
break;
}
pList = insertNode( pList, pPre, insertData );
}
else
printf("That country ID already exists. Please try again.");
return pList;
}
int insertHandler ( DATA *data, char target[] )
{
// Local Declarations
int position = 0;
// Statements
if ( ! ( data->list.name = (char*)calloc(21, sizeof(char)))) {
printf("Memory Unavailable.\n");
exit(300);
}
if ( ! ( data->list.capital = (char*)calloc(16, sizeof(char)))) {
printf("Memory Unavailable.\n");
exit(400);
}
strcpy ( data->key, target );
printf("Enter the country's name: ");
scanf("%s", data->list.name);
FLUSH;
printf("Enter the country's capital: ");
scanf("%s", data->list.capital);
FLUSH;
printf("Enter the country's population: ");
scanf("%ld", &(data->list.population));
FLUSH;
while ( position < 1 || position > 3 ) {
printf("Where would you like to place this new country?\n"
"Beginning(1), Middle(2), End(3): ");
scanf("%d", &position);
FLUSH;
if ( position < 1 || position > 3 )
printf("Incorrect option. Please try again.\n");
}
return position;
} // insertHandler
NODE *deleteNode (NODE *pList, NODE *pPre, NODE *pCur)
{
// Statements
if ( pPre == NULL )
pList = pCur->link;
else
pPre->link = pCur->link;
free ( pCur );
return pList;
} // deleteNode
NODE *deleteManager (NODE *pList)
{
// Local Declarations
NODE *pPre = NULL;
NODE *pCur;
char target[3];
// Statements
printf("Please enter a key: ");
scanf("%2s", target);
FLUSH;
if ( searchList ( pList, &pPre, &pCur, target ) )
pList = deleteNode ( pList, pPre, pCur );
else
printf("Country could not be found. Please try again.");
return pList;
} // deleteManager
NODE *destroyList (NODE *pList)
{
// Local Declarations
NODE *pPre = NULL;
NODE *pCur;
// Statements
while ( pList ) {
pCur = pList;
free ( pCur->data.list.name );
free ( pCur->data.list.capital );
pList = deleteNode ( pList, pPre, pCur );
}
return pList;
} // destroyListInput file:
HU Hungary; Budapest; 10006835
MX Mexico; Mexico; 106202903
CN China; Beijing; 1306313812
NP Nepal; Kathmandu; 27676547
MU Mauritius; Port Louis; 1230602
FR France; Paris; 60656178
ES Spain; Madrid; 40341462
EG Egypt; Cairo; 77505756
TW Taiwan; Taipei; 22894384
GR Greece; Athens; 10668354
US United States; Washington, DC; 295734134
AU Australia; Canberra; 20090437
LI Liechtenstein; Vaduz; 33717
RU Russia; Moscow; 143420309
CA Canada; Ottawa; 32805041
MC Monaco; Monaco; 32409
BR Brazil; Brasilia; 186112794
IR Iran; Tehran; 68017860
FR France; Paris; 60656178
DO Dominican Republic; Santo Domingo; 8950034
FJ Figi; Suva; 893354