I'm suppose to read a file and then write to the file in an alphabatically sorted array. However, I am keep getting a segmentation fault using gdb, indicating my display and sort function occur segmentation fault.
EDIT: I fixed it by use a macro to allocate memory. Since it is an assignment, I do not wish to disclose it just in case. I do appreciate everyone's help on my code.
You're supposed to do this? Ouch.
I got a segfault too, but in read_names(). I was able to fix it by replacing all the strtok() stuff with a simple scanf():
void read_names (FILE *fp, char **f, char **l, char *m, int num)//read it
{
int i=0;
char temp[80];
for (i=0; i<num; i++)
{
fscanf( fp, "%s %s %s", f[i], l[i], m);
}
}
After that I was able to sort & print, though it's trying to free() something erroneously at the end.
I general strtok() is insecure and just a pain - it destroys your string.
Also, more meaningful names make it easier to work with. I eventually figured out that "l[]" was an array of strings containing the last name, but something along the lines of "sLastName[]" would have sped that up immensely.
EDIT:
I gathered your input text file looked like this:
2 bill smith a doug adams r
EDIT2:
OK, found another segfault. What is "num"? It seems to be interpreted as kindof the number of names in the file and kindof the size of each name?
// allocate "num" first name elements -> implied "num" is # of names
f=(char**)malloc (num*sizeof(char*));
// allocate space for each name... but uses the value of "num" for each name
for (i=0; i<num;i++)
f[i]=(char*)malloc (num*sizeof(char)); // "num" bytes per name?
When I started allocating 100 bytes per name instead of the value of "num", the second - and for me last - segfault went away.
Did you enter the entire program and then start testing? It would be a lot easier to get it working in small steps then incrementally adding functionality - verifying with debugger and/or printf() that it's doing what you want at each step.
