读取数据文件作为链表中的节点的功能

Question

My text file reads as this: George Washington, 2345678 John Adams, 3456789 Thomas Jefferson, 4567890 James Madison, 0987654 James Monroe, 9876543 John Quincy Adams, 8765432 Andrew Jackson, 7654321 Martin Van Buren, 6543210

However, when I run my current code to display I don't get those numbers and end up with random ones, how can I fix this? You can avoid the other functions for now as I am just trying to make sure the file reads into different nodes.

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

//Creates node for holding student's information
struct node
{
char name [50];
int id;
struct node *next;
}*head;

//Create Function Prototypes
void readDataFile ();
void display(struct node *d);
void deleteID(int num);
void deleteName(char dname);


//Main function
int main()
{
//Declare variables
int i, num, intid;
char *name;
char nameDelete [50];
char nameInsert [50];
struct node *n;

//initialize link list
head = NULL;

//Read in file
readDataFile();

//Create list of operations utilized in program
while (1)
{
    printf("\nList Operations\n");
    printf("===============\n");
    printf("1.Insert\n");
    printf("2.Display\n");
    printf("3.Delete by ID\n");
    printf("4.Delete by Name\n");
    printf("5.Exit\n");
    printf("Enter your choice : ");

    if(scanf("%d", &i) <= 0)
    {
        printf("Enter only an Integer\n");
        exit(0);
    }
    else
    {
        switch(i)
        {
            case 1:
                printf("Enter the name to insert: ");
                gets(nameInsert);
                printf("Enter the ID associated with the name: ");
                scanf("%d", &intid);
                break;
            case 2:
                if (head == NULL)
                    printf("List is Empty\n");
                else
                {
                    printf("Elements in the list are:\n");
                }
                display(n);
                break;
            case 3:
                if(head == NULL)
                    printf("List is Empty\n");
                else
                {
                    printf("Enter the ID number to delete: ");
                    scanf("%d", &intid);
                }
                break;
            case 4:
                if(head == NULL)
                    printf("List is Empty\n");
                else
                {
                    printf("Enter name to delete: ");
                    gets(nameDelete);
                }
            case 5:
                return 0;
            default:
                printf("Invalid option\n");
        }
    }
}
return 0;
}

Answer 1

The problem you have is not the reading but the printing .

printf("Student %s has ID %d\n", d->name, &d->id);

You use the address-of operator & when reading with scanf (and family), but when you're printing it will print the address of the variable.

---

You also have some other problem with the reading of the file, besides what I mentioned in my comment, and that is your none-linking:

temp->next = malloc(sizeof(struct node));
temp = temp->next;
temp->next = NULL;

This will create an extra node at the end of the list, which will be uninitialized meaning that when you use the data it will lead to undefined behavior .

Actually, with the problem mentioned in my comment you will have two extra nodes.