Thread: Sorted Linked List with multiple heads.

Hi there i've been tinkering with this program for a while and think i have it figured out, but i'm getting some segmentation faults and memory issues.

Here are my issues, if i understoud them i'd fix them but to be honest i've been experimenting with this code alot and it's whooping my butt haha

1. When i select option 1. i can enter new info, and print it out. BUT if i choose option 1 again to add another entry to the list i get a seg fault.

2. When i select option 2 to remove an entry i type the name and it finds it and removes it then gives me a seg fault.

3. When i add a struct then search for a record that's not there when i print the struct back out it says the list is empty?

can someone go over my code and let me know if it makes any sense at all, i've found this problem very hard to solve solely using *nextName and *nextAge.

Thanks, ALain

Code:

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

#define MAX_LEN 250

typedef struct node 
{
    char *name;
    int  age;
    struct node *nextName;
    struct node *nextAge;
}NODE;

int drain_stdin()
{
    int c;

    while((c = getchar()) != '\n' && c != EOF);

    return c;
}

NODE * listInput(NODE *new)
{

    new = malloc(sizeof(NODE));
	new->name = malloc(sizeof(char)*MAX_LEN + 1);    
    
    if (drain_stdin() != EOF)
    {
        printf("Enter name: ");
        fgets(new->name, MAX_LEN + 1, stdin);

        printf("Enter age: ");
        scanf("%d", &new->age);
    }
    else
    {
        printf("An Error Has Occured\n");
    }
    return new;
}

NODE * insertNameNode(NODE *new, NODE *head1)
{
    NODE *temp;
    NODE *prev;

    new->nextName = NULL;
    
    if (head1 == NULL)
    {
        return new;     
    }

    temp = head1;
    prev = NULL; 
    
    while(1) 
    {

	    if (strcmp(temp->name, new->name) < 0) 
        {
		    prev = temp; 
		    temp = temp->nextName;      
		    continue; 
	    }
        else if(strcmp(temp->name, new->name) >= 0) 
        {
	        new->nextName = temp;   	
            
	        if (prev != NULL)
            {
                prev->nextName = new;  
            }
	        else
            {
                head1 = new;  
	            break; 
            }
        }
    }
    return (head1);    
}

NODE * insertAgeNode(NODE *new, NODE *head2)
{
    NODE *temp;
    NODE *prev;

    new->nextAge = NULL;

    if (head2 == NULL)
    {
        return new;     
    }

    temp = head2;
    prev = NULL; 
    
    while(1) 
    {

	    if (temp->age < new->age) 
        {
		    prev = temp; 
		    temp = temp->nextAge;      
		    continue; 
	    }
        else if(temp->age >= new->age) 
        {
	        new->nextAge = temp;   	
            
	        if (prev != NULL)
            {
                prev->nextAge = new;  
            }
	        else
            {
                head2 = new;  
	            break; 
            }
        }
    }
    return(head2);
}

NODE * removeNameStruct(NODE *head1, char *nameRemove)
{
    NODE *prev;
    NODE *root;    

    prev = NULL;
    root = head1;    
   
    if (drain_stdin() != EOF )
    {
        printf("Enter Name Of Desired Record To Be Removed: ");
        fgets(nameRemove, MAX_LEN + 1, stdin);

        while (head1 != NULL) 
        { 
            if(strcmp(nameRemove, root->name) == 0)
            {
                printf("Found The Record\n");

                if (prev != NULL)
                {
                    prev->nextName = head1->nextName;
                }
                else
                {
                    root = head1->nextName; 
                }
                free(head1);
                break;
            } 
            else 
            {
                printf("Record NOT Found\n");
     		    prev = head1; 
			    head1 = head1->nextName;
		    }
        }
    }
    else
    {
        printf("An Error Has Occured\n");
    } 
    return (head1);
}

NODE * removeAgeStruct(NODE *head2, char *nameRemove)
{

    NODE *prev;
    NODE *root;

    prev = NULL;   
    root = head2;    

    while (head2 != NULL) 
    { 
        if(strcmp(nameRemove, root->name) == 0)
        {
            printf("Found The Record\n");

            if (prev != NULL)
            {
                prev->nextAge = head2->nextAge;
            }
            else
            {
                root = head2->nextAge;
            }
            free(head2);
            break;
        } 
        else 
        {
            printf("Record NOT Found\n");
            prev = head2;
            head2 = head2->nextAge;
	    }
    }
    return (head2);
}

void printName(NODE *head1, NODE *head2)
{
    if (head1 == NULL) 
    { 
		printf("List is empty.\n") ; 
		return; 
	}
    else
    {    
        while (head1 != NULL) 
        {
            printf("%s %d\n", head1->name, head2->age);
            head1 = head1->nextName;
        }
    }
}

void printAge(NODE *head1, NODE *head2)
{
    if (head2 == NULL) 
    { 
		printf("List is empty.\n") ; 
		return ; 
	}
    else
    {    
        while (head2 != NULL) 
        {
            printf("%s %d\n", head2->name, head2->age);
            head2 = head2->nextAge;
        }
    }
}


void freeProg(NODE *head1, NODE *head2)
{
    while(head1 != NULL && head2 != NULL)
    {
        free(head1->name);    
        free(head1);
        free(head2->name);    
        free(head2);
    }     
}


int main(void) 
{
    int choice, count;
    char nameRemove[MAX_LEN + 1];

    choice = 0;
    count = 0;

    NODE *new;
    NODE *head1;
    NODE *head2;
    
    new = NULL;
    head1 = NULL;
    head2 = NULL;

    do
    {
        printf("1. Add structure\n");
        printf("2. Remove structure\n");
        printf("3. Print names\n");    
        printf("4. Print ages\n");
        printf("5. Exit\n");
        scanf("%d", &choice);

        if(choice == 1)
        {
            new = listInput(new);
            head1 = insertNameNode(new, head1);
            head2 = insertAgeNode(new, head2);
        }
        else if(choice == 2)
        {
            head1 = removeNameStruct(head1, nameRemove);
            head2 = removeAgeStruct(head2, nameRemove);
        }

        else if(choice == 3)
        {
            printName(head1, head2);
        }
        else if(choice == 4)
        {
            printAge(head1, head2);
        }
        else if(choice == 5)
        {
            freeProg(head1, head2);
        }   
        else
        {
            return 0;
        }
        
    }while(choice != 5);    

    return 0;
}