Help -- allocating memory in a multidimensional array
I need some help with allocating memory. This is for a school assignment and the notes I've taken in class aren't quite helping me solve the problem.
Basically I have a list of words and I make sentences from those words. I've drawn a '-->>' next to the part of the code that is causing a segmentation fault. Please help me understand why.
I have the following variables:
Code:
char **data[4];
int numOf[] = {0,0,0,0};
and here is my insane function that is giving me a segmentation fault
Code:
void addWord(char *type, char *word)
{
// compare() just returns a 1 if the word matches, or a 0 if not
int t = compare(type, "article")?0:compare(type, "noun")?1:compare(type, "verb")?2:3;
// This method dynamically increases the size of my array. The code is below
increaseArray(t);
int n = 0;
// If there's nothing there ... add something there
if (numOf[t] == 0)
{
data[t][0] = malloc(sizeof(char)*strlen(word));
strcpy(data[t][0], word);
numOf[t]++;
printLists();
return;
}
// Otherwise add in sorted order
else
{
for (n = 0; n < numOf[t]; n++)
{
// compareTo() returns a -1 if it's less than, 1 if greater than, or 0 if equal
// like in java
if (compareTo(word, data[t][n]) < 0)
{
int i;
for (i = 0; i < numOf[t]-n; i++);
{
// So this is what's breaking ... I allocate memory at the end of my
// list equal to the size of the item 1 from the end, then I copy the item
// from 1 from the end into the end, rinse and repeat down the list
// backwards. However it breaks on the first attempt to move a word
-->> data[t][numOf[t]-i] = malloc(sizeof(char)*strlen(data[t][numOf[t]-i-1]));
strcpy(data[t][numOf[t]-i], data[t][numOf[t]-i-1]);
}
data[t][n] = malloc(sizeof(char)*strlen(word));
strcpy(data[t][n], word);
numOf[t]++;
printLists();
return;
}
// If our word already exists....just ignore it
else if (compareTo(word, data[t][n]) == 0) { printLists(); return; }
}
// If we've gone through the list and not added it by now, then
// it is obviously going to go to the end of the list...so let's
// allocate memory and put it in!
strcpy(data[t][n], word);
numOf[t]++;
printLists();
return;
}
}
// Here is my method for increasing my array dynamically. This may be part of my
// problem, and I'm sure there's an easier way.
void increaseArray(int list)
{
auto char **tempArray[4];
tempArray[0] = malloc(numOf[0]);
tempArray[1] = malloc(numOf[1]);
tempArray[2] = malloc(numOf[2]);
tempArray[3] = malloc(numOf[3]);
int x = 0, y = 0, z = 0;
for (x = 0; x < 4; x++)
{
for (y = 0; y < numOf[x]; y++)
{
tempArray[x][y] = malloc(sizeof(char)*strlen(data[x][y]));
for (z = 0; z < strlen(data[x][y]); z++)
{
tempArray[x][y][z] = data[x][y][z];
}
}
}
data[list] = malloc(numOf[list]+1);
for (x = 0; x < 4; x++)
{
for (y = 0; y < numOf[x]; y++)
{
data[x][y] = malloc(sizeof(char)*strlen(tempArray[x][y]));
for (z = 0; z < strlen(tempArray[x][y]); z++)
{
data[x][y][z] = tempArray[x][y][z];
}
}
}
}
