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If fuction in Linked Lists

This is a discussion on If fuction in Linked Lists within the C Programming forums, part of the General Programming Boards category; hello this its me again. im having trouble using the if function in a linked list. so basically i wanted ...

  1. #1
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    Oct 2007
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    8

    If fuction in Linked Lists

    hello this its me again. im having trouble using the if function in a linked list. so basically i wanted to count how many nodes contains a character as its element in a linked list. basically it has 5 nodes and all of them has a char element. this is what i had come up with and i am stuck because it seems that the statement for total is not being executed.

    Code:
    #include<stdio.h>
    #include<conio.h>
    #include<ctype.h>
    void main()
    {
    int total=0;
    struct list{
    char value;
    struct list *next;
    }a,b,c,d,e;
    struct list *p;
    a.value='A';
    a.next=&b;
    b.value='B';
    b.next=&c;
    c.value='C';
    c.next=&d;
    d.value='D';
    d.next=&e;
    e.value='E';
    e.next=NULL;
    p=&a;
    
    struct list *rec_ptr;
    rec_ptr=p;
    printf("The elements are:\n");
    while(rec_ptr!=NULL){
    printf("\t%c\n",rec_ptr->value);
    rec_ptr=rec_ptr->next;}
    
    
    
    rec_ptr=p;
    while(rec_ptr!=NULL){
    if(isalpha(rec_ptr->value)==0){
    total=total+1;}
    rec_ptr=rec_ptr->next;}
    
    printf("\nTotal Nodes with Character Elements is %d",total);
    getch();
    }
    the output for total is 0, instead of 5. pls anyone can help me?

  2. #2
    and the hat of wrongness Salem's Avatar
    Join Date
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    Read this -> SourceForge.net: Indentation - cpwiki
    Read this -> SourceForge.net: Void main - cpwiki
    Read this -> isalpha(3): char classification routines - Linux man page
    Code:
    #include<stdio.h>
    #include<ctype.h>
    int main()                      //!! fixed
    {
      int total = 0;
      struct list {
        char value;
        struct list *next;
      } a, b, c, d, e;
      struct list *p;
      a.value = 'A';
      a.next = &b;
      b.value = 'B';
      b.next = &c;
      c.value = 'C';
      c.next = &d;
      d.value = 'D';
      d.next = &e;
      e.value = 'E';
      e.next = NULL;
      p = &a;
    
      struct list *rec_ptr;
      rec_ptr = p;
      printf("The elements are:\n");
      while (rec_ptr != NULL) {
        printf("\t%c\n", rec_ptr->value);
        rec_ptr = rec_ptr->next;
      }
    
      rec_ptr = p;
      while (rec_ptr != NULL) {
        if (isalpha(rec_ptr->value) != 0) { //!! read the manual, what does isalpha() return?
          total = total + 1;
        }
        rec_ptr = rec_ptr->next;
      }
    
      printf("\nTotal Nodes with Character Elements is %d", total);
      return 0;                     //!! fixed
    }
    Some things (like strcmp) return 0 when things match.
    Other things (like isalpha) return 0 when things DO NOT match.
    rswest likes this.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
    Registered User
    Join Date
    Oct 2007
    Posts
    8
    thank you salem. sorry for the late reply. your links that you shared help a lot. im now on my final term in programming c. i was given a proect to make a hangman game in C. i have seen a few here on the site. if i encounter some problems ( im pretty sure i will! ) ill post it here and i hope you will help me again. you are very kind salem. thank you

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