Thread: Linked list program, not recognizing a function

I'm writing a linked list program for class that has a simple text based menu and I believe I am nearly done, it just wont recognize my "count" function as a function and I don't know why. Was hoping someone could point a something simple I'm overlooking.

The error comes up at line 70.

Code:

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


typedef struct node
{
    int datum;
    struct node *next;
} node_t;


node_t * prepend(node_t *, int);
void print_list(node_t *);
node_t * append(node_t *, int);
node_t * delete(node_t *, int);
int contains(node_t *, int);
int count(node_t *, int);


int 
main(int argc, const char **argv)
{


    int check, count, selection, listnum;
    node_t *list;
    list = NULL;


  printf("1. Prepend an Item\n");
  printf("2. Append an Item\n");
  printf("3. Delete an Item\n");
  printf("4. Check for an Item\n");
  printf("5. Count the number of items\n");
  printf("6. Print the list\n");
  printf("7. Quit\n");
  printf("Choose an option: ");
  scanf("%d", &selection);


  do
  {


switch(selection){
    case 1:
      printf("What number would you like to prepend?\n");
      scanf("%d", &listnum);
      list = prepend(list, listnum);
      break;
    case 2:
      printf("What number would you like to append?\n");
      scanf("%d", &listnum);
      list = append(list, listnum);
      break;
    case 3:
      printf("What number would you like to delete?\n");
      scanf("%d", &listnum);
      list = delete(list, listnum);
      break;
    case 4:
      printf("What number would you like to check for?\n");
      scanf("%d", &listnum);
      check = contains(list, listnum);
      printf("%d\n", check);
      break;
    case 5:
      printf("What number would you like to count?\n");
      scanf("%d", &listnum);
      printf("Count is %d\n",count(list, listnum));
     break;
    case 6:
      print_list(list);
      break;
    case 7:
     /**/
     break;
    default:
      printf("Invalid selection\n");
      break;
  }


  } while (selection != 7);


    return 0;
}


node_t *
prepend(node_t *head, int x)
{
    node_t *nhead = (node_t*)malloc(sizeof(node_t));
    nhead->datum = x;
    nhead->next = head;
    head = nhead;
    return head;
}


void 
print_list(node_t *head)
{


    if (head == NULL){
        printf("NULL");
    } else {
        printf("%d->",head->datum);
        print_list(head->next);
    }
}


node_t *
append(node_t *head, int x)
{
    if(head == NULL){
        head = (node_t*)malloc(sizeof(node_t));
        head->datum = x;
        head->next = NULL;
    }    else{
        head ->next = append(head->next,x);
    }
    return head;
}


node_t *
delete(node_t *head, int x)
{
    if (head == NULL){
        return head;
    }    else if (head->datum==x){
        node_t *tail = head->next;
        head->next=NULL;
        free(head);
        return tail;
    }    else {
        head->next = delete(head->next,x);
        return head;
    }
    
}


int
contains(node_t *head, int x)
{
    if(head == NULL){
        return 0;
    }    else if(head->datum == x){
        return 1;
    }    else{
        return contains(head->next, x);
    }
}


int
count(node_t *head, int x)
{
    node_t *ptr;
    int count;
    count = 0;


    for(ptr = head; ptr != NULL; ptr = ptr->next){
        if(ptr->datum == x){
            count++;
        }
    }


    return count;
}

Compile at maximum warning level and/or get a better compiler with better diagnostic messages:

Code:

$ make foo
gcc -Wall -ggdb3 -pedantic -std=gnu99 -O0 -o foo foo.c -lm -lpthread -lrt
foo.c: In function ‘main’:
foo.c:70:45: error: called object ‘count’ is not a function or function pointer
                 printf("Count is %d\n",count(list, listnum));
                                             ^
foo.c:25:16: note: declared here
     int check, count, selection, listnum;
                ^
make: *** [foo] Error 1

Notice that you have a function and variable with the same name. The compiler is rightly confused. One, or both of those, should have a more descriptive name, such as a function count_all_the_things() and a variable count_of_things, or number_of_things.

Thank you! That fixed that problem.

Now I've run it and seem to get stuck inside a single option. ("Now what would you like to append?" '5' "Now what would you like to append?"......"

Is the do while loop unnecessary? I'm not super familiar with switch statements so I wasn't sure.

Nevermind, I realized I simply left out the menu from the do while loop, thanks for your help!