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Binary search tree help needed

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Binary search tree help needed

 
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  #1
Jul 25th, 2009
Hello all,

in time of need I always come here to cry for help)

Anyways. What I need to do is to store data about people in a binary tree. They need to come from a file, but for now I can hardcode them in.

To put it simple, I will have 10 people (probably defined as structures with name, surname, age, phone number variables) where surname acts as a key.

I am totally new to binary trees - does it mean I will need to have a tree of structures? I have some sample code, but it only works for numbers, how can I modify it so it will take structures?

How do I go about it? General tips and even code would be great!

Also, I found some sample code and it has weird "->" symbols - what do they mean in my context?

Basically, I need a good push.

Thanks!
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Re: Binary search tree help needed

 
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  #2
Jul 26th, 2009
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Originally Posted by Lioshenka View Post
Hello all,

in time of need I always come here to cry for help)

Anyways. What I need to do is to store data about people in a binary tree. They need to come from a file, but for now I can hardcode them in.
Well, I suppose the first thing you could code is the input function and get that out of the way...

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Originally Posted by Lioshenka View Post
To put it simple, I will have 10 people (probably defined as structures with name, surname, age, phone number variables) where surname acts as a key.

I am totally new to binary trees - does it mean I will need to have a tree of structures? I have some sample code, but it only works for numbers, how can I modify it so it will take structures?
Yes. How to modify your code? Replace the integer data field with your structure data. The integer information is already defined in a structure, is it not? Just replace it with all the fields you need to keep track of.

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Originally Posted by Lioshenka View Post
How do I go about it? General tips and even code would be great!
Use your editor... Since you posted nothing, I can only guess -- or use my psychic powers. Which would you like me to do?

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Originally Posted by Lioshenka View Post
Also, I found some sample code and it has weird "->" symbols - what do they mean in my context?
A structure element is referenced using a dot, as in person.age , get the age field from the person structure. But if the structure is a pointer, you use ->. In this case if person is your structure, and p_person points to the person structure, get the age with p_person->age
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Re: Binary search tree help needed

 
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  #3
Jul 29th, 2009
c Syntax (Toggle Plain Text) 
  1. #include <stdio.h>
  2. #include <string.h>
  3. #include <stdlib.h>
  4.  
  5. int main()
  6. {
  7.  
  8.     typedef struct{
  9.             char dummy[256];
  10.             char surname[225];
  11.             char name[256];
  12.             int ID;
  13.             char house[256];
  14.             char street[256];
  15.             char town[256];
  16.             char county[256];
  17.             char area[256];
  18.             char country[256];
  19.             char postcode[256];
  20.             int phone;
  21.             char email[256];
  22.             char boattype[256];
  23.             char boatname[256];
  24.             }user;
  25.  
  26. FILE *file;
  27. int i=0;
  28. char number_of_people[256];
  29. int nop;
  30. char yetdummy[256]; 
  31. char yetdummy2[256]; 
  32.  
  33.  
  34.  file = fopen("members.data","r");
  35.  if(file==NULL) {
  36.     printf("Error: can't open file.\n");
  37.     return 1;
  38.   }
  39.   else {
  40.     printf("File opened successfully.\n");
  41.          }
  42.  fscanf(file,"%s \n", number_of_people);
  43.  //printf("%s \n", number_of_people);
  44.  
  45.  nop = atoi(number_of_people);
  46.  //printf("%d\n", nop);
  47.  user usera[nop]; 
  48.   for (i=0; i<nop; i++){
  49.       fgets(usera[i].dummy, 256, file);        
  50.       fgets(usera[i].surname, 256, file);  
  51.       fgets(usera[i].name, 256, file);  
  52.       fgets(yetdummy, 256, file);  
  53.       usera[i].ID = atoi(yetdummy);      
  54.       fgets(usera[i].house, 256, file);  
  55.       fgets(usera[i].street, 256, file);  
  56.       fgets(usera[i].town, 256, file); 
  57.       fgets(usera[i].county, 256, file);  
  58.       fgets(usera[i].area, 256, file);  
  59.       fgets(usera[i].country, 256, file);  
  60.       fgets(usera[i].postcode, 256, file);  
  61.       fgets(yetdummy2, 256, file); 
  62.       usera[i].phone = atoi(yetdummy2);
  63.  
  64.       fgets(usera[i].email, 256, file);  
  65.       fgets(usera[i].boattype, 256, file);  
  66.       fgets(usera[i].boatname, 256, file);        
  67.  
  68.      printf("Name is %s\n", usera[i].name);      
  69.       printf("ID is %d\n", usera[i].ID);    
  70.  }
  71.  
  72.   fclose(file);
  73.  
  74. }

This is my code so far. I got it to read members from file and it works fine and reads them all in an array of structures. You can probably see how stupid I am in programming if you look at my code)))

What can I do next? This is the sample code I was talking about earlier, I think it is very similar to what I am looking for, but I can not see how the student data is fed into the program or how the key variable is defined...
c Syntax (Toggle Plain Text) 
  1. #include<stdlib.h>
  2. #include<stdio.h>
  3.  
  4. typedef struct student_data STUDENT_DATA;
  5.  
  6. struct student_data {
  7.  int student_ID;
  8.  int student_grade;
  9.  STUDENT_DATA *left, *right;
  10. };
  11.  
  12. STUDENT_DATA *new_student, *cur_student;
  13.  
  14. if ((new_student = malloc(sizeof(STUDENT_DATA))) == NULL) { abort(); }
  15.  
  16. new_student->student_ID = newID;
  17. new_student->student_size = newsize;
  18. new_student->left = NULL;
  19. new_student->right = NULL;
  20.  
  21. if (!students) { students = new_student; return; }
  22.  
  23. cur_student = students;
  24. while (cur_student) { 
  25.  
  26. if (newID == cur_student->student_ID) { abort(); }
  27.  
  28. if (newID < cur_student->student_ID) {
  29.  if (cur_student->left == NULL) {
  30.  cur_student->left = newstudent;
  31.  return 1;
  32.  }
  33.  cur_student = cur_student->left;
  34.  
  35.  } else {
  36.  if (cur_student->right == NULL) {
  37.  cur_student->right = newstudent;
  38.  return 1;
  39.  }
  40.  cur_student = cur_student->right;
  41.  }
  42. }

Thanks a lot!

Oh, and by the way I use Dev-C++
Last edited by Lioshenka; Jul 29th, 2009 at 6:26 pm.
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Re: Binary search tree help needed

 
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  #4
Aug 2nd, 2009
Anyone, please?? How do I use binary tree with the structures?
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