c++ - Linked List error when inserting for the last time -

so have part of code here

this loop 5 times (max = 5) insert word link list.

for ( int = 0 ; < max ; i++ ) {     string alphabet = g->returnalphabets();      l[i]->addwords(alphabet[i]); } 

and have insert word part here

string line;  fstream myfile ("words.txt");  while (!myfile.eof()) {     getline(myfile,line);      if ( alphabet == line[0] )     {         listnode *newnode = new listnode;          if ( head == null )         {             newnode->item = alphabet;                        newnode->next = null;             head = newnode;         }          else         {             newnode->item = line;                            prev = cur;             prev->next = newnode;         }          cur = newnode;     } }  myfile.close(); 

my problem gives me error on last loop. meaning on max = 4, insert node. rest of loop fine. when decrease max 4 meaning loop 4 times, program error-free when program loops 5 times gives error.

anyone can point me mistakes?

edit:

i've detected during last loop, doesn't go first node.
, program word file gives error when entering first node

the logic using while (!myfile.eof()) bad because not check getline(myfile, line); succeeded, , proceed use value when getline() detected eof. should using:

while (getline(myfile, line)) {     ...rest of loop... } 

it not clear (to me) without scrutinizing manuals or standard state of line after failed getline(), lead line[0] failing.

since "it failing on last iteration", principal cause of trouble.