Why wont file data save to structure? - c

Question

I don't understand what I'm doing wrong here. I have a program that successfully reads in data from a file. Once it does this the data that was read in SHOULD be able to be searched/shown/or deleted, but it does not do this. I know the file is being successfully read because when I add a printf() to the function reading the file, it prints out the correct data. Help would be wonderful. Here is the stripped down version of the code.
typedef struct friends_contact{
char *First_Name;
char *Last_Name;
char *home;
char *cell;
}fr;
int main()
{
fr friends[5];
char buffer[BUFFSIZE];
int counter=0;
int i=0;
menu(friends, &counter,i,buffer);
getch();
return 0;
}
//Menu function
void menu(fr*friends,int* counter, int i,char buffer[])
{
int user_entry=0;
int user_entry1=0;
int user_entry2=0;
char user_entry3[50]={'\0'};
FILE *read;
printf("Welcome! Would you like to import a file? (1)Yes or (2) No");
scanf("%d",&user_entry1);
if(user_entry1==1)
{
printf("Please enter a file name");
scanf("%s",user_entry3);
read=fopen(user_entry3,"r");
}else;
do{
int result;
printf("\nPhone Book Application\n");
printf("1) Add friend\n2) Delete friend\n3) Show a friend\n4) Show phonebook\n5)Exit\n");
scanf("%d", &user_entry);
if(user_entry==1)
{
add_contact(friends,counter,i,buffer);
}
if(user_entry==2)
{
delete_contact(friends ,counter,i);
}
if(user_entry==3)
{
result=show_contact(friends ,counter,i);
if(result==0){
printf("\nName not Found\n");
}else{
result;
}
}
if(user_entry==4)
{
print_contact(friends, counter,i,user_entry3);
if(user_entry1==1)
{
file2(friends ,counter,i,buffer,read);
}else;
}
}while(user_entry!=5);
}
The delete function
//This is used to delete a name out of the book
char delete_contact(fr*friends ,int* counter, int i)
{
char name_search[50]={'\0'};
char Delete[5]={'\0'};
printf("Search by last name\n");
scanf("%s",name_search);//Name entry
for(i=0;i<*counter;i++)
{
if(strcmp(name_search,friends[i].Last_Name)==0)//Copys over the name entered
{
strcpy(friends[i].Last_Name,Delete);
}
}
//Freeing up memory.
free(friends[i].First_Name);
free(friends[i].Last_Name);
free(friends[i].home);
free(friends[i].cell);
printf("\nName(s) has been deleted\n");
}
the print function:
//This function prints out all the contact information
void print_contact(fr*friends ,int* counter, int i,char user_entry3[50])
{
for( i = 0; i < *counter; i++)
if (strlen(friends[i].First_Name) && strlen(friends[i].Last_Name)&& strlen(friends[i].home)&& strlen(friends[i].cell ))
{
getFirst(friends, i);
getLast(friends, i);
getHome(friends, i);
getCell(friends, i);
}
}
//Displays the contact in which you are searching for.
int show_contact(fr*friends ,int* counter, int i)
{
char name_search2[50]={'\0'};
int flag=0;
printf("Please enter a last name\n");
scanf("%s",name_search2);
for(i=0;i<*counter;i++)
{
//If the name is found, it reaturns the contact info.Now works for duplicate last names.
if(strcmp(name_search2,friends[i].Last_Name)==0)
{
(strlen(friends[i].First_Name) && strlen(friends[i].Last_Name)&& strlen(friends[i].home)&& strlen(friends[i].cell ));
getFirst(friends, i);
getLast(friends, i);
getHome(friends, i);
getCell(friends, i);
flag++;
}
}
return flag;
}
The Read in function:
void file2(fr*friends ,int* counter, int i,char buffer[],FILE*read)
{
fseek(read, 0, SEEK_SET);
while (fscanf(read,"%s", buffer) != EOF)
{
friends[*counter].Last_Name=malloc(BUFFSIZE*strlen(buffer));
strcpy(friends[*counter].Last_Name, buffer);
printf("%s\n",friends[*counter].Last_Name);
}
}

Answer 1

Try changing your read function to something like this where you pass in the size of your friends array so you don't read in too many lines and end up crashing your program. This is assuming you are reading in line by line from a text file.
This will loop while our counter is less than the number of elements in our friends array to ensure we don't go out of bounds while accessing each of the structures, OR if we reached the end of file, then it will stop.
To allocate memory for Last_Name we take the length of the string that got stored in buffer and add 1 to make room for the null terminating byte.
void file2(fr *friends, const size_t num_friends, FILE *read)
{
size_t counter = 0;
char buffer[128];
while (counter < num_friends && fscanf(read, "%s", buffer) != EOF) {
friends[counter].Last_Name = malloc(strlen(buffer) + 1);
strcpy(friends[counter].Last_Name, buffer);
counter++;
}
}
Then call this like file2(friends, 5, read); The middle argument is the size of your array.
fscanf can also overflow your buffer if you supply it with too much data. It has no bounds checking which can lead to crashing your program. I'd look into using fgets instead for next time.