Struct infile

Comments

• Donotalo

  April 2006

  : I'm infiling a struct and for whatever reason I just can't figure out what I need to do to get this to work.
  :
  : [code]
  : int main(){
  :
  : char cdNum[11];
  : char cdTitle[41];
  : long qtyOnHand;
  : double cost;
  : CDRec* Inventory;
  : int count=0;
  :
  : ifstream infile("cd.txt");
  :
  : if(!infile){
  : cerr << "Error: File does not exist
  ";
  : exit(0);
  : }
  : char c;
  : while(infile.get(cdNum, sizeof(cdNum))){
  : if(infile.eof())
  : break;
  :
  : infile>>ws;
  : infile.get(cdTitle, sizeof(cdTitle));
  : infile >> qtyOnHand >> cost;
  : infile>>ws;
  : Inventory = new CDRec(cdNum, cdTitle, qtyOnHand, cost);
  : count++;
  : }
  : infile.close();
  : for(int i =0; i < count; i++){
  : cout << Inventory[i].cdNum << setw(13) << Inventory[i].cdTitle << setw(43) << Inventory[i].qtyOnHand << setw(5) << Inventory[i].cost <<endl;
  : }
  : return 0;
  : }
  : [/code]
  :
  : The problem seems to be the while loop. I'm not used to inputting a char string first. The input of the struct works fine. Any help would be greatly appreciated.
  :
  [purple]
  ur style of keeping [blue]CDRec[/blue] items in [blue]Inventory[/blue] is errorneous. u must allocate sufficient memory for [blue]Inventory[/blue] to hold all the items found in the file.
  what is [blue]ws[/blue]? it is not defined. why r u using it?
  make ur code organized while reading from a file. read all [blue]Inventory[/blue] values, then check for the end of file.
  u shud also mention clearly what is the expected output u r looking for.
  [/purple]
  [hr][purple]~Donotalo()[/purple]
  
  
• tsagld

  April 2006

  : I'm infiling a struct and for whatever reason I just can't figure out what I need to do to get this to work.
  :
  : [code]
  : int main(){
  :
  : char cdNum[11];
  : char cdTitle[41];
  : long qtyOnHand;
  : double cost;
  [red] CDRec** Inventory = calloc(1024, sizeof(CDRec*)) //alloc space for 1024 pointers.[/red]
  : int count=0;
  :
  : ifstream infile("cd.txt");
  :
  : if(!infile){
  : cerr << "Error: File does not exist
  ";
  : exit(0);
  : }
  : char c;
  : while(infile.get(cdNum, sizeof(cdNum))){
  : if(infile.eof())
  : break;
  :
  : infile>>ws;
  : infile.get(cdTitle, sizeof(cdTitle));
  : infile >> qtyOnHand >> cost;
  : infile>>ws;
  [red] Inventory[count] = new CDRec(cdNum, cdTitle, qtyOnHand, cost); [/red]
  : count++;
  : }
  : infile.close();
  : for(int i =0; i < count; i++){
  : cout << Inventory[i].cdNum << setw(13) << Inventory[i].cdTitle << setw(43) << Inventory[i].qtyOnHand << setw(5) << Inventory[i].cost <<endl;
  [red]
  /* Don't forget to release memory!!!!
  for(i =0; i < count; i++){
  delete Inventory[i];
  }
  free(Inventory);
  [/red]
  : }
  : return 0;
  : }
  : [/code]
  :
  : The problem seems to be the while loop. I'm not used to inputting a char string first. The input of the struct works fine. Any help would be greatly appreciated.
  :
  With your old line
  [code]
  Inventory = new CDRec(cdNum, cdTitle, qtyOnHand, cost);
  [/code]
  you lose the previous CDRec, and create a memory leak.
  The problem is that you want Inventory to be an array of CDRec's but you are using it as a pointer to one instance of CDRec.
  I corrected that in the red lines in the above code.
  
  
  Greets,
  Eric Goldstein
  www.gvh-maatwerk.nl
  
  
  
• EPenguin

  April 2006

  : : I'm infiling a struct and for whatever reason I just can't figure out what I need to do to get this to work.
  : :
  : : [code]
  : : int main(){
  : :
  : : char cdNum[11];
  : : char cdTitle[41];
  : : long qtyOnHand;
  : : double cost;
  : : CDRec* Inventory;
  : : int count=0;
  : :
  : : ifstream infile("cd.txt");
  : :
  : : if(!infile){
  : : cerr << "Error: File does not exist
  ";
  : : exit(0);
  : : }
  : : char c;
  : : while(infile.get(cdNum, sizeof(cdNum))){
  : : if(infile.eof())
  : : break;
  : :
  : : infile>>ws;
  : : infile.get(cdTitle, sizeof(cdTitle));
  : : infile >> qtyOnHand >> cost;
  : : infile>>ws;
  : : Inventory = new CDRec(cdNum, cdTitle, qtyOnHand, cost);
  : : count++;
  : : }
  : : infile.close();
  : : for(int i =0; i < count; i++){
  : : cout << Inventory[i].cdNum << setw(13) << Inventory[i].cdTitle << setw(43) << Inventory[i].qtyOnHand << setw(5) << Inventory[i].cost <<endl;
  : : }
  : : return 0;
  : : }
  : : [/code]
  : :
  : : The problem seems to be the while loop. I'm not used to inputting a char string first. The input of the struct works fine. Any help would be greatly appreciated.
  : :
  : [purple]
  : ur style of keeping [blue]CDRec[/blue] items in [blue]Inventory[/blue] is errorneous. u must allocate sufficient memory for [blue]Inventory[/blue] to hold all the items found in the file.
  : what is [blue]ws[/blue]? it is not defined. why r u using it?
  : make ur code organized while reading from a file. read all [blue]Inventory[/blue] values, then check for the end of file.
  : u shud also mention clearly what is the expected output u r looking for.
  : [/purple]
  : [hr][purple]~Donotalo()[/purple]
  :
  :
  Thanks for the help everyone, I ended up just rewriting the input so that it was a function and tested for the eof that way.
  
  
  ws is defined in Visual Studio as "white space".
  
• tsagld

  April 2006

  : : : I'm infiling a struct and for whatever reason I just can't figure out what I need to do to get this to work.
  : : :
  : : : [code]
  : : : int main(){
  : : :
  : : : char cdNum[11];
  : : : char cdTitle[41];
  : : : long qtyOnHand;
  : : : double cost;
  : : : CDRec* Inventory;
  : : : int count=0;
  : : :
  : : : ifstream infile("cd.txt");
  : : :
  : : : if(!infile){
  : : : cerr << "Error: File does not exist
  ";
  : : : exit(0);
  : : : }
  : : : char c;
  : : : while(infile.get(cdNum, sizeof(cdNum))){
  : : : if(infile.eof())
  : : : break;
  : : :
  : : : infile>>ws;
  : : : infile.get(cdTitle, sizeof(cdTitle));
  : : : infile >> qtyOnHand >> cost;
  : : : infile>>ws;
  : : : Inventory = new CDRec(cdNum, cdTitle, qtyOnHand, cost);
  : : : count++;
  : : : }
  : : : infile.close();
  : : : for(int i =0; i < count; i++){
  : : : cout << Inventory[i].cdNum << setw(13) << Inventory[i].cdTitle << setw(43) << Inventory[i].qtyOnHand << setw(5) << Inventory[i].cost <<endl;
  : : : }
  : : : return 0;
  : : : }
  : : : [/code]
  : : :
  : : : The problem seems to be the while loop. I'm not used to inputting a char string first. The input of the struct works fine. Any help would be greatly appreciated.
  : : :
  : : [purple]
  : : ur style of keeping [blue]CDRec[/blue] items in [blue]Inventory[/blue] is errorneous. u must allocate sufficient memory for [blue]Inventory[/blue] to hold all the items found in the file.
  : : what is [blue]ws[/blue]? it is not defined. why r u using it?
  : : make ur code organized while reading from a file. read all [blue]Inventory[/blue] values, then check for the end of file.
  : : u shud also mention clearly what is the expected output u r looking for.
  : : [/purple]
  : : [hr][purple]~Donotalo()[/purple]
  : :
  : :
  : Thanks for the help everyone, I ended up just rewriting the input so that it was a function and tested for the eof that way.
  :
  :
  : ws is defined in Visual Studio as "white space".
  :
  
  Not sure what you did, but you still have a major memory leak issue in your code.
  
  Greets,
  Eric Goldstein
  http://www.gvh-maatwerk.nl/english/E_index.htm