Problem in c programming?

Re _Record:

name needs to allocate some memory. Either you need to allocate name at run time, or before. Here I wasted 32 bytes for the name allocation. The alternative is that you i.e. had an array of c strings and point name to this existing memory location.

Otherwise assignment to name would remain local

This piece of code:

you are declaring local variables y and a and fill them from the file. Then over and over again you point the variable pointing to char (*name) to the address of y. Your printf statement would output the last content of y.

As the variable age has allocation for sizeof(int), this variable changes according to file content.

After the function createLinkedList is exited, the variable y ceases existing. location to the address stored will reflect "undefined" content. I hope the disaster of your function becomes a bit clearer. I would help you discussing this more in-depth, in case you e-mail your questions.

Have fun.

while(!(feof(fp)))

{

fscanf(fp,"%s",y);

fscanf(fp,"%d",&a);

localHead->name=y;

localHead->age=a;

printf("%d %s",localHead->age,localHead->name);

localHead->next=(struct _Record*)malloc(sizeof(struct _Record));

localHead=localHead->next;

}

------------------------

Start of corrected code

------------------------

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

typedef struct _Record{

char name[32];

unsigned int age;

struct _Record *next;

} Record;

Record* createLinkedList(const char *fileName);

void deleteRecords(Record **listHead, const char *fileName);

void insertRecords(Record **listHead, const char *fileName);

void printLinkedList(Record *listHead, const char *fileName); /*prints linked list to file*/

void sortLinkedList(Record **listHead);

int main()

{

Record *head = createLinkedList("allRecords.txt");

printf("%s\n",head->name);

printLinkedList(head, "readRecords.txt");

sortLinkedList(&head);

printLinkedList(head, "afterSort.txt");

deleteRecords(&head, "deleteList.txt");

printLinkedList(head, "afterDelete.txt");

insertRecords(&head, "insertList.txt");

printLinkedList(head, "afterInsert.txt");

return 0;

}

void printLinkedList(Record *listHead, const char *fileName)

{

FILE *fp;

char s[40];

printf("Printing linked list to file %s\n", fileName);

strcpy(s,fileName);

//fp=fopen(s,"r");

}

void sortLinkedList(Record **listHead)

{

/*Sort the linked list by Age (ascending order)*/

}

Record* createLinkedList(const char *fileName)

{

Record *localHead, *temp;

FILE *fp;

printf("Loading records from file %s \n",fileName);

localHead = malloc(sizeof(struct _Record));

localHead->next = NULL;

temp = localHead;

fp = fopen(fileName,"rt");

while(!feof(fp)) {

if (fscanf(fp, "%s\n", temp->name) != 1) {

break;

}

if (fscanf(fp, "%d\n", &temp->age) != 1) {

break;

}

temp->next = NULL;

if (!feof(fp)) {

temp->next = malloc(sizeof(struct _Record));

temp = temp ->next;

}

}

fclose(fp);

temp = localHead;

while(temp) {

printf("[%s %d]\n", temp->name, temp->age);

temp = temp->next;

}

return localHead;

}

void deleteRecords(Record **listHead, const char *fileName)

{

printf("Deleting records from file %s \n",fileName);

}

void insertRecords(Record **listHead, const char *fileName)

{

printf("Inserting records from file %s \n",fileName);

}

See the troubleshooting guide here: http://ubuntuforums.org/showthread.php?t=691451