C/C++ :: Tokenize Mathematical Expression - Garbage Value In String

I wrote a program that tries to tokenize a mathematical expression, inserting the tokens in a list of strings. The list is as follows:

typedef struct listOfStrings {
    char **array;
    int size;
} ListOfStrings;

There is even a function to initialize the listOfStrings. The thing is: I'm printing a token every time it is complete and every time it is inserted in the list. The output is okay. However, when all tokens are processed and I call function print_list_of_strings to print the tokens again, the first token is printed with a leading garbage value if the input for the program is "3 + 4 * 2 / ( 1 - 5 ) ^ 2 ^ 3". How is this possible? The code for printing the list is as follows:

void print_list_of_strings( const ListOfStrings *const lPtr ) {
    int i;
    int numberOfElements = lPtr->size;  
    if ( numberOfElements != 0 ) {
        for ( i = 0 ; i < numberOfElements ; ++i ) {

[Code] ....

The list just prints --- if it's empty, although this isn't the case for the program I'm writing. Also, if the input is "1 + 2", everything goes fine. The code for inserting at the list is:

int insert_at_end_of_list_of_strings( ListOfStrings *lPtr, const char *const str ){
    int lengthOfStr = strlen( str );
    int numberOfElements = lPtr->size;  
    if ( ( ( *( lPtr->array + numberOfElements ) ) = ( char * )malloc( ( lengthOfStr + 1 ) *
 
[Code] ....