Thread: Linked List Issues

Really struggling with this project, when I go to use my display function it errors out, I know I'm missing something as my understanding is not all that high.

Code:

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

struct N{
char shipName[25];
char shipType;
int hostage;
int shipValue;
int ransom;
struct N* next;
}*LOG;

void add(char ship[25], char type, int hostage, int shipValue, int ransom);
void display(); 
int length();

int main()
{

LOG=NULL;

int choice, hostage, ransom, shipValue;

char ship[25], type;


    while(1){

printf("Main Menu\n");
printf("1. See A Captured Ship's Information\n");
printf("2. Add a Ship\n");
printf("3. Remove a Ship\n");
printf("4. Generate Report (textfile)\n");
printf("5. Exit\n");
scanf("%d", &choice);
 
 
 switch(choice)  
    {  
    case 1:
            printf(" \nThere Are %d ships in the list\n",length()); 
            display();
            
    break;
    case 2:
    printf("Shipname:\n");
    scanf("%s", &ship);
    printf("Ship Type(T = Tanker, S = Schooner, Y= Yacht):\n");
    scanf("%s", &type);
    printf("Hostage:\n");
    scanf("%d", &hostage);
    printf("Ship Value:\n");
    scanf("%d", &ransom);
    printf("RANSOM:\n");
    scanf("%d", &shipValue);
  
            add(ship, type, hostage, shipValue, ransom); 
    break;
    case 3:
    break;
    case 4:
    break;
    case 5:
        exit(0);
    }
}
}

void add(char ship[], char type, int hostage, int shipValue, int ransom)  
{  
  struct N *temp1, *temp2;  
  
  temp1=(struct N *)malloc(sizeof(struct N)); 
  temp1->shipName[25]=ship[25];
  temp1->shipType=type;
  temp1->hostage=hostage;
  temp1->shipValue=shipValue;
  temp1->ransom=ransom;
 
  temp2=LOG;  
  
  if(LOG == NULL)  
  {  
     //First Node.  
     LOG=temp1;  
     LOG->next=NULL;  
  }  
  else  
  {  
     // End of the list.  
     while(temp2->next != NULL)  
     temp2=temp2->next;  
  
     // End of the list.  
     temp1->next=NULL;  
     temp2->next=temp1;  
  }  
}  

int length()  
{  
  struct N *ptr;  
  int count=0;  
  
  ptr=LOG;  
  
  while(ptr != NULL)  
  {  
     ptr=ptr->next;  
     count++;  
  }  
  return(count);  
}  

void display()  
{  
  struct N *ptr;  
  ptr=LOG;  
  
  if(ptr==NULL)  
  {  
     printf("\nNo Ship Logs");  
  }  
  else  
  {  

      while(ptr != NULL)  
      {  
            printf("Ship Name: %s\n", ptr->shipName);
            printf("Type: %s\n", ptr->shipType);  
            printf("Number of Hostages: %d\n", ptr->hostage);  
            printf("Ship Value: %d\n", ptr->shipValue);  
            printf("Ransom Demanded: %d\n", ptr->ransom);  
          ptr=ptr->next;  
      }  
      printf("\n");  
  }  
}

Code:

   
   scanf("%s", &ship);
Should be
    scanf("%s", ship);

It's already an address to something

The scanfs from lines 50 to 56 are using the wrong format specifier, and the one on line 48 is slightly wrong for the reason already given.

Originally Posted by Matticus

That was already brought up in this thread, in case you missed it.



strcpy - C++ Reference

Ok but how would I do that with a pointer?

Code:

strcpy(temp1->shipName, ship);

doesn't seem to work.

This is where I'm at right now, output for shipName isn't working correctly

Code:

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

struct N{
int j;
char shipName[25];
char shipType;
int hostage;
int shipValue;
int ransom;
struct N* next;
}*LOG;

void add(char ship[], char type, int hostage, int shipValue, int ransom);
void display(); 
int length();

int main()
{

LOG=NULL;

int choice, hostage, ransom, shipValue, loc;

char ship[25], type;


    while(1){

printf("Main Menu\n");
printf("1. See A Captured Ship's Information\n");
printf("2. Add a Ship\n");
printf("3. Remove a Ship\n");
printf("4. Generate Report (textfile)\n");
printf("5. Exit\n");
scanf("%d", &choice);
 
 
 switch(choice)  
    {  
    case 1:
            printf(" \nThere Are %d ships in the list\n",length()); 
            display();
            
    break;
    case 2:{
    printf("Shipname:\n");
    scanf("%s", ship);
    printf("Ship Type(T = Tanker, S = Schooner, Y= Yacht):\n");
    scanf("%s", &type);
    printf("Hostage:\n");
    scanf("%d", &hostage);
    printf("Ship Value:\n");
    scanf("%d", &ransom);
    printf("RANSOM:\n");
    scanf("%d", &shipValue);
            add(ship, type, hostage, shipValue, ransom); }
    break;
    case 3: {
          printf(" \nWhich Entry Do You Wish To Delete ");  
          scanf("%d",&loc);  
          delLoc(loc);  
          display();  }
    break;
    case 4:{
    FILE *fp;
    fp=fopen("log.txt", "w");
    struct N *this;

    if(LOG == NULL)

    {
        printf("This is Empty\n");
       break;
    }
     for ( this = LOG ; this != NULL ; this = this->next ) {
    fwrite(this, sizeof(*this), 1, fp);
}
    
    }
    
    break;
    case 5:
        exit(0);
    }
}
}

void add(char ship[], char type, int hostage, int shipValue, int ransom)  
{  
  struct N *temp1, *temp2;  
  static int j=0;
  
  temp1=(struct N *)malloc(sizeof(struct N)); 
  temp1->j=j++;
  strcpy(temp1->shipName, ship);
  temp1->shipType=type;
  temp1->hostage=hostage;
  temp1->shipValue=shipValue;
  temp1->ransom=ransom;
 
  temp2=LOG;  
  
  if(LOG == NULL)  
  {  
     //First Node.  
     LOG=temp1;  
     LOG->next=NULL;  
  }  
  else  
  {  
     // End of the list.  
     while(temp2->next != NULL)  
     temp2=temp2->next;  
  
     // End of the list.  
     temp1->next=NULL;  
     temp2->next=temp1;  
  }  
}  

int length()  
{  
  struct N *ptr;  
  int count=0;  
  
  ptr=LOG;  
  
  while(ptr != NULL)  
  {  
     ptr=ptr->next;  
     count++;  
  }  
  return(count);  
}  

void display()  
{  

  struct N *ptr;  
  ptr=LOG;  
  
  if(ptr==NULL)  
  {  
     printf("\nNo Ship Logs");  
  }  
  else  
  {  

      while(ptr != NULL)  
      {  
            printf("Entry Number %d\n", ptr->j);
            printf("Ship Name: %s\n", ptr->shipName);
            printf("Type:%c\n", ptr->shipType);  
            printf("Number of Hostages: %d\n", ptr->hostage);  
            printf("Ship Value: %d\n", ptr->shipValue);  
            printf("Ransom Demanded: %d\n", ptr->ransom);  
            
          ptr=ptr->next;  
      }  
      printf("\n");  
  }  
}  

int delLoc(int loc)  
{  
  struct N *prev_ptr, *ptr;  
  int i;  
  
  ptr=LOG;  
  
  if(loc > (length()) || loc <= 0)  
  {  
      printf("\nDeletion of LOG is not possible\n ");  
  }  
  else  
  {  
      // If the location is starting of the list  
      if (loc == 1)  
      {  
          LOG=ptr->next;  
          free(ptr);  
          return 0;  
      }  
      else  
      {  
          for(i=1;i<loc;i++)  
          {  
              prev_ptr=ptr;  
              ptr=ptr->next;  
          }  
  
          prev_ptr->next=ptr->next;  
          free(ptr);  
      }  
  }  
  return 1;  
}