pointer called by reference doesnt work - c

Question

Hi i have a problem with the next code which i had posted before here, but yesterday i was working on my computer and all of the sudden the screen froze and when i restarted it my code was gone!! it was erased, so i had to start over. The code had to search a codop in a linked list, but it doesnt work, i keep getting the message "CODOP NOT FOUND", i thought that the problem was in the calling of pointers as pass by value, so i called it by reference but it doesnt work either, if someone could tell me how to solve it i would apreciate it a lot
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct node
{
char *instruction;
struct node *next;
}COD;
void printList(COD *head);
void SearchEndLine(FILE *hc12);
void listTABOP(COD **head);
COD *lastElement(COD **head);
COD *createNode(char *ins);
void insertEnd(char *ins,COD *last);
char *Operands_Table(FILE *hc12);
COD *searchCodop(COD *head,char *codop);
void Remove(char *c);
int main()
{
COD *head = NULL,*found = NULL;
char *codop = "BLE";
listTABOP(&head);
printList(head);
if((found = searchCodop(head,codop)) == NULL)
{
printf("CODOP NOT FOUND\n");
printf("%s\n",codop);
}
return 0;
}
void SearchEndLine(FILE *hc12)
{
int car;
while((car = fgetc(hc12))!= '\n')
;
}
void Remove(char *c)
{
char *ptr;
if(((ptr = strchr(c,'\n'))!= NULL)||((ptr = strchr(c,'\t'))!= NULL)||((ptr = strchr(c,' '))!= NULL))
*ptr = '\0';
}
void listTABOP(COD **head)
{
int car;
FILE *hc12;
COD *last = NULL;
char *ins;
if((hc12 = fopen("Tabla_OP.txt","r"))!= NULL)
{
while((car = fgetc(hc12))!= EOF)
{
if(car != '\t')
{
ins = Operands_Table(hc12);
if(*head == NULL)
*head = createNode(ins);
else
{
last = lastElement(head);
insertEnd(ins,last);
}
}
else
SearchEndLine(hc12);
}
}
else
printf("No se pudo abrir el archivo");
}
COD *lastElement(COD **head)
{
COD *ptr;
ptr = *head;
while(ptr->next != NULL)
ptr = ptr->next;
return ptr;
}
char *Operands_Table(FILE *hc12)
{
int car,lon = 0,pos;
char *c;
fseek(hc12,-1,SEEK_CUR);
pos = ftell(hc12);
do
{
car = fgetc(hc12);
lon++;
}while(car != '\t');
fseek(hc12,pos,SEEK_SET);
c = (char*)calloc((lon+1),sizeof(char));
fgets(c,lon+1,hc12);
Remove(c);
SearchEndLine(hc12);
return c;
}
COD *searchCodop(COD *head,char *codop)
{
COD *ptr;
for(ptr = head;ptr != NULL;ptr = ptr->next)
{
if(ptr->instruction == codop)
return ptr;
}
return NULL;
}
void insertEnd(char *ins,COD *last)
{
last->next = createNode(ins);
last->next->next = NULL;
last = last->next;
}
COD *createNode(char *ins)
{
int s;
COD *x;
x = (COD*)malloc(sizeof(COD));
s = strlen(ins);
x->instruction = (char*)malloc((s+1)*sizeof(char));
strcpy(x->instruction,ins);
x->next = NULL;
return x;
}
void printList(COD *head)
{
COD *ptr;
for(ptr = head;ptr != NULL;ptr = ptr->next)
printf("\n%s\n",ptr->instruction);
}

Answer 1

The problem is with this line:
if(ptr->instruction == codop)
it compares address of strings not strings themselves.
Use strcmp or something like that instead.