Thread: An access violation (segmentation fault) was raised in your program. HELP!

Hi all i have completed my c program but i receive the error "An access violation (segmentation fault) was raised in your program." When debugging in Dev c++ it fails to go past the int main() and brings up this error. I cant seem to find where the error is. Help would be greatly appreciated.

Code:

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

typedef struct GeocentricCelestialReferenceFrame {
int x;
int y;
int z;
} GCRF;

typedef struct DiscoveredPlanet {
int usersConfirmed;
int type;
GCRF*coordinates;
struct DiscoveredPlanet* next;
} discPlanet;

typedef struct VerifiedPlanet {
int type;
GCRF*coordinates;
struct VerifiedPlanet* next;
} verPlanet;

typedef struct userWorkCompleted {
char firstName[20];
char lastName[20];
int gbAnalyzed;
int planetsDiscovered;
struct userWorkCompleted* next;
} userWork;

typedef enum {
NONE = 0,
GAS = 1,
ICE = 2,
STORM = 3,
BARREN = 4,
TEMPERATE = 5,
LAVA = 6,
OCEANIC = 7,
PLASMA = 8,
UNKNOWN = 9
} Planets;

//Declare userLists 
userWork *userList = NULL;
discPlanet *discList = NULL;
verPlanet *verList = NULL;
userWork *currentUser = NULL;
discPlanet *currentDisc = NULL;
verPlanet *currentVer = NULL;

userWork *insertUser(userWork *userList, char *first, char *last);
discPlanet *confirmedPlanets(discPlanet* listDisc, verPlanet* listVer, int typePlanet, int x, int y, int z);

int main(){
    int entries, i, analyzed, discovered, x, y, z;
    char first, last;
    
    
    
    //Scan in input file and number of entries
    FILE *fp;
    fp = fopen("GridComputing.in","r");
    fscanf(fp, "%d" , &entries);

//Initialize for loop for number of entries
    for(i=0; i<entries; i++){
   
        fscanf(fp, "%s %s", first, last);
        fscanf(fp, "%d", &analyzed);
        fscanf(fp, "%d", &discovered); 
        
        currentUser = insertUser(userList, &first, &last);
        currentUser->gbAnalyzed = currentUser->gbAnalyzed + analyzed;
        
        if(discovered != 0){
            currentUser->planetsDiscovered++;
            fscanf(fp, "%d %d %d", &x, &y, &z); 
            currentDisc = confirmedPlanets(discList, verList, discovered, x, y, z);
        }
            
    }
    fclose(fp);
        
    fp = fopen("GridComputing.out", "w");
    
    fprintf(fp, "Users:\n");
    currentUser = userList;
    
    userWork* userTemp;
    while(currentUser != NULL){
        fprintf(fp, "\t%s, %s - Analyzed:%d\n", currentUser->lastName, currentUser->firstName, currentUser->planetsDiscovered);
        userTemp = currentUser;
        currentUser = currentUser->next;
        free(userTemp);
    }
    
    fprintf(fp, "\nDiscovered Planets:\n");
    currentDisc = discList;
    
    discPlanet* discTemp;
    while(currentDisc != NULL){
        
        fprintf(fp, "\t(%d,%d,%d) - Confirmed:%d Type:%d\n", currentDisc->coordinates->x, currentDisc->coordinates->y, currentDisc->coordinates->z, currentDisc->usersConfirmed, currentDisc->type);
        discTemp = currentDisc;
        currentDisc = currentDisc->next;
        free(discTemp->coordinates);
        free(discTemp);
    }
    
    fprintf(fp, "\nVerified Planets:\n");
    currentVer = verList;
    
    verPlanet* verTemp;
    while(currentVer != NULL){
        
        fprintf(fp, "\t(%d,%d,%d) - Type:%d\n", currentVer->coordinates->x, currentVer->coordinates->y, currentVer->coordinates->z, currentVer->type);
        verTemp = currentVer;
        currentVer = currentVer->next;
        free(verTemp->coordinates);
        free(verTemp);
    }
    
    
    fclose(fp);
    
    return 0;
}


userWork *insertUser(userWork *userList, char *first, char *last) {

  userWork *temp;
  userWork *current;


  // Create the new node.
  temp = (userWork*)malloc(sizeof(userWork));
  temp->next = NULL;

  // Take care of case inserting into an empty userList.
  if (userList == NULL){
         temp=(userWork*)malloc(sizeof(userWork));
         temp->next = NULL;
         
         strcpy(temp->firstName, first);
         strcpy(temp->lastName, last); 
         
         temp->gbAnalyzed = 0; 
         
         temp->planetsDiscovered = 0; 
         
         userList=temp;
         
         return temp;
}

if(stricmp(last, userList->lastName)== 0){
        
        if(stricmp(first, userList->firstName) == 0){
            return userList;
        }
        
        else if(stricmp(first, userList->firstName)< 0){
            temp=(userWork*)malloc(sizeof(userWork));
            strcmp(temp->firstName, first);
            strcmp(temp->lastName, last);
            temp->gbAnalyzed = 0;
            temp->planetsDiscovered = 0; 
            
            
            temp->next = userList; 
            
            userList = temp;
            
            return temp;    
        }
    }
    else if(stricmp(last, userList->lastName) < 0){
        temp=(userWork*)malloc(sizeof(userWork));
        strcmp(temp->firstName, first);
        strcmp(temp->lastName, last); 
        
        temp->gbAnalyzed = 0;
        temp->planetsDiscovered = 0; 
        
        temp->next = userList; 
        
        userList = temp;
        
        return temp;
    }

    while(current->next != NULL) {
    
        if(stricmp(first, current->next->firstName) == 0){
            
            if(stricmp(last, current->next->lastName) == 0){
                return current->next;
            }
        
            else if(stricmp(first, current->next->firstName) < 0){
                temp=(userWork*)malloc(sizeof(userWork));
                strcmp(temp->firstName, first);
                strcmp(temp->lastName, last);
                temp->gbAnalyzed = 0;
                temp->planetsDiscovered = 0;
                temp->next = current->next;
                current->next = temp;
            
                return temp;
            }
        }
        else if(stricmp(last, current->next->lastName) < 0){
            temp=(userWork*)malloc(sizeof(userWork));
            strcpy(temp->firstName, first);
            strcpy(temp->lastName, last);
            temp->gbAnalyzed = 0;
            temp->planetsDiscovered = 0; 
            temp->next = current->next; 
            
            current->next = temp; 
            
            return temp;
        }
        
        current = current->next;
    }
    
    temp=(userWork*)malloc(sizeof(userWork));
    strcpy(temp->firstName, first);
    strcpy(temp->lastName, last);
    temp->gbAnalyzed = 0; 
    temp->planetsDiscovered = 0; 
    temp->next = NULL;
    current->next = temp; 
    return temp; 
}

discPlanet* confirmedPlanets(discPlanet *listDisc, verPlanet *listVer, int typePlanet, int x, int y, int z){
    discPlanet *dpNew = NULL;
    
    if(listDisc == NULL){
        listDisc=(discPlanet*)malloc(sizeof(discPlanet));
        listDisc->usersConfirmed = 1;
        listDisc->type = typePlanet;
        listDisc->coordinates = (GCRF*)malloc(sizeof(GCRF));
        listDisc->coordinates->x = x;
        listDisc->coordinates->y = y;
        listDisc->coordinates->z = z;
        listDisc->next = NULL; 
        return listDisc;
    }
    
    discPlanet* temp = (listDisc);
    discPlanet* temp2 = (listDisc);
    
    while(temp != NULL){
        if((temp->coordinates->x == x) && (temp->coordinates->y == y) && (temp->coordinates->z == z)){
            temp->usersConfirmed++;
            
            if(temp->usersConfirmed >= 3){
                return NULL;
            }
        return temp;
        }
        if(temp->next == NULL){ 
            break;
        }
        temp = temp->next;
    }
    
    temp2 = (discPlanet*)malloc(sizeof(discPlanet));
    temp2->usersConfirmed = 1;
    temp2->type = typePlanet;
    temp2->coordinates = (GCRF*)malloc(sizeof(GCRF));
    temp2->coordinates->x = x;
    temp2->coordinates->y = y;
    temp2->coordinates->z = z;
    temp2->next = NULL;
    temp->next = temp2;
    return temp2;
}

i was compiling the whole time and didnt get the error until i finished the program. Iv tried debugging but cant seem to find where it is crashing. What is the best way to debug?

Originally Posted by wo0dy

i was compiling the whole time and didnt get the error until i finished the program.

So, it worked until you put in the last bit... Apply head to problem.... which section did you work on last?

As far as debugging goes, that varies from OS to OS and IDE to IDE... so we're going to need a bit more information to give you a good answer.

Originally Posted by wo0dy

i was compiling the whole time and didnt get the error until i finished the program. Iv tried debugging but cant seem to find where it is crashing. What is the best way to debug?

As Quzah points out .... "Compiles" absolutely does not mean "Works"... it only means you didn't tick off the compiler.

A few things, right of the start in main(). You never check if you successfully open the file, then you attempt to use fscanf to read in strings in two variables (first, last) declared char.

Originally Posted by wo0dy

i was compiling the whole time and didnt get the error until i finished the program. Iv tried debugging but cant seem to find where it is crashing. What is the best way to debug?

What they are talking about is, when you write a function, debug and test to make sure the function does what you want it to. Then move to the next function, do the same, and so on.

For debugging, it was suggested to us in my class to use GDB.

GDB, pretty much compile with the -g flag and you can run GDB.

Another tool we use also is Valgrind (great for spotting mem leaks). The trick with Valgrind is fix the first problem at the top, and run it again, and work down.