Hello !
I am using Turbo C++ compiler and I am trying to implement Dictionary using arrays. All my menu options work perfectly but finally when I give exit option the program comes out of Turbo C++ and gives a window saying
"The program tried to execute an invalid instruction "
"Fault Location : 6172 : 74E6"
and the MS-DOS window closes.
Can you help me trouble shoot this problem ?
Sandra John
//Ex. No. 2.4 Date : 16/08/04
//Dictionary implementation using arrays
//Sandra Johnson Reg. No. : 200431977
#include"d:\dsalab\ex2\dic_arr.h"
//structure of the hash table
struct element
{
ordered_list *word; //pointer to an ordered list of words
ordered_list *mean; //pointer to an ordered list of meanings
};
//dictionary class
class dictionary
{
private:
struct element *table; //pointer to the structure of table
int tablesize; // size of the table
public:
dictionary(); //default constructor
dictionary(unsigned int x); //overloaded constructor
~dictionary(); //destructor
int insert(char *wrd,char *men); //insert a new word in the dictionary
int search(char *wrd); //search for a word
int search(char ch); //search for a word starting with a char
int search_mean(char *men);//search for a word given a meaning
int search_sub(char *men); //search for words with a substring
int hash(char*wrd); //maps the word to a location in the table
void getinput(char *wrd,char *men); //reads the word , meaning pair
void getword(char *wrd); //reads a word
void getwordchar(char *wr); //reads a char
void message(int er); //message display routine
void message(char *wrd,char *men); //displays the word,meaning
int menu(); //menu routine
};
dictionary::~dictionary() //destructor
{
delete[] table; //deallocates the hash table
}
dictionary::dictionary()
{
table=new struct element[rows]; //allocates the memory for table
for(unsigned int i=0;i<rows;i++)
{
table[i].word=NULL; //initializes the table with null
table[i].mean=NULL;
}
tablesize=rows;
}
dictionary::dictionary(unsigned int x)
{
table=new struct element[x]; //allocates the memory for table
for(unsigned int i=0;i<x;i++)
{
table[i].word=NULL; //initializes the table with null
table[i].mean=NULL;
}
tablesize=x;
}
int dictionary::hash(char *wrd)
{
int hh=toascii(wrd[0]); //maps words starting with a,A to 0
if (hh >= 97) //maps words starting with b,B to 1
hh=hh-97; //and so on
else
hh=hh-65;
return hh;
}
//inserts word, meaning into the dictionary
int dictionary::insert(char *wrd,char *men)
{
int found,hs;
ordered_list *swrd,*smen;
hs=hash(wrd); //find the index in the table
swrd=table[hs].word; //get the pointer to the word ordered list
smen=table[hs].mean; //get the pointer to the meaning ordered list
if (swrd == NULL) //word not in the dictionary
{
ordered_list *myword,*mymen;
myword=new ordered_list(minrow);
swrd=table[hs].word=myword;
mymen=new ordered_list(minrow);
smen=table[hs].mean=mymen;
}
found=swrd->search_loc(wrd);
if (found >= 0) //word already found in the dictionary
{
message(1);
message(swrd->retrieve_ol(found),smen->retrieve_ol(found));
}
else
{
unsigned int loc=swrd->find_loc(wrd);
swrd->insert_ol(loc,wrd);
smen->insert_ol(loc,men);
message(5);
}
return 1;
}
//search the dictionary for the given word
int dictionary::search(char *wrd)
{
int found=-1;
ordered_list *swrd,*smen;
swrd=table[hash(wrd)].word; //get the pointer to the word ordered list
smen=table[hash(wrd)].mean; //get the pointer to the meaning ordered list
if (swrd == NULL) //no word starting at the same char in dictionary
{
message(2);
}
else
{
found=swrd->search_loc(wrd);
if (found >= 0)
{
message(3);
message(swrd->retrieve_ol(found),smen->retrieve_ol(found));
}
else //word not in dictionary
message(2);
}
return found;
}
//search the dictionary for all the words for a given meaning
int dictionary::search_mean(char *men)
{
int found=-1,i,len;
ordered_list *swrd,*smen;
for(i=0;i<tablesize;i++) //search the table
{
swrd=table[i].word;
smen=table[i].mean;
if (swrd != NULL)
{
len=swrd->get_length();
for(int j=0;j<len;j++) //search each ordered list
{
char *temp=smen->retrieve_ol(j);
int ck=strcmp(men,temp);
if (ck == 0)
{
found=1;
message(swrd->retrieve_ol(j),temp);
}
}
}//end of if
}//end of for i
if (found == -1) message(2);
return found;
}
//search the dictionary for all the words with a given substring
int dictionary::search_sub(char *men)
{
int found=-1,i,len;
ordered_list *swrd,*smen;
for(i=0;i<tablesize;i++) //search the table
{
swrd=table[i].word;
smen=table[i].mean;
if (swrd != NULL)
{
len=swrd->get_length();
for(int j=0;j<len;j++) //search each ordered list
{
char *temp=swrd->retrieve_ol(j);
char *ck=strstr(temp,men);
if (ck != NULL)
{
found=1;
message(temp,smen->retrieve_ol(j));
}
}
}//end of if
}//end of for i
if (found == -1)
message(6);
return found;
}
//search the dictionary for all the words starting in a given char
int dictionary::search(char ch)
{
int found=-1;
char *chw;
chw[0]=ch;
chw[1]='\0';
int l=hash(chw); //hash the char to a table location
ordered_list *swrd,*smen;
swrd=table[l].word; //get the pointer to the ordered lists
smen=table[l].mean; // of word , meaning
if (swrd == NULL) //no word starting in the char
{
message(4);
}
else
{
found=1;
int len=swrd->get_length();
for(unsigned int i=0;i<len;i++) //display all the words,meaning
message(swrd->retrieve(i),smen->retrieve(i));
}
return found;
}
void dictionary::getinput(char *wrd,char *men)
{
clrscr();
cout<<"\n\n\t\t\tINSERT NEW WORD ";
cout<<"\n\n\tEnter the word : ";
scanf("%[^\n]s",wrd);
fflush(stdin);
//cin>>wrd;
cout<<"\n\n\tEnter the meaning :";
scanf("%[^\n]s",men);
fflush(stdin);
//cin>>men;
}
void dictionary::getword(char *wrd)
{
clrscr();
cout<<"\n\n\t\t\tSEARCH THE WORD ";
cout<<"\n\n\tEnter the word : ";
cin>>wrd;
}
void dictionary::getwordchar(char *wr)
{
clrscr();
cout<<"\n\n\t\t\tSEARCH THE WORDS - FOR THE STARTING CHARACTER ";
cout<<"\n\n\tEnter the character : ";
cin>>*wr;
}
//message routine used to display different messages
void dictionary::message(int er)
{
switch(er)
{
case 1:
cout<<"\n\t\t\tWord Already in dictionary...\n";
break;
case 2:
cout<<"\n\t\t\tWord not in dictionary..........\n";
break;
case 3:
cout<<"\n\t\t\tWord is in dictionary...\n";
break;
case 4:
cout<<"\n\t\t\tWord starting with the character not in dictionary..\n";
break;
case 5:
cout<<"\n\t\tInsertion successfull....\n";
break;
case 6:
cout<<"\n\t\tWord with the substring not in the dictionary....\n";
break;
default : break;
};
}
//displays the word and the message
void dictionary::message(char *wrd,char *men)
{
cout<<"\n\n\t\t";
cout<<wrd<<"------->"<<men<<"\n";
}
//displays the menu for the dictionary class
int dictionary::menu()
{
int choice;
// do
// {
clrscr();
cout<<"\t\t\t\tDictionary\n\n\n";
cout<<"\t\t1. Insert word.\n\n";
cout<<"\t\t2. Search word.\n\n";
cout<<"\t\t3. Search for a char.\n\n";
cout<<"\t\t4. Search a substring.\n\n";
cout<<"\t\t5. Search for a meaning.\n\n";
cout<<"\t\t6. Exit.\n\n";
cout<<"\t\tEnter the choice (1-6) : ";
cin>>choice;
// }
// while ((choice < 1) && (choice >6));
return choice;
}
int main()
{
clrscr();
int opt;
char *wr,*mn,cr;
dictionary D;
do
{
opt=D.menu();
switch (opt)
{
case 1: //insert a new word,meaning
D.getinput(wr,mn);
D.insert(wr,mn);
break;
case 2: //search for a word
D.getword(wr);
D.search(wr);
break;
case 3: //search for all words starting in a char
D.getwordchar(&cr);
D.search(cr);
break;
case 4: //search for words with a substring
clrscr();
cout<<"\n\n\n\t\tEnter a search substring :";
cin>>mn;
cout<<"\n\n";
D.search_sub(mn);
break;
case 5: //search for words given their meaning
clrscr();
cout<<"\n\n\n\t\tEnter meaning :";
cin>>mn;
cout<<"\n\n";
D.search_mean(mn);
break;
case 6:
return 1;
//exit(0);
//break;
default:
cout<<"\n\n\t\t\tEnter (1-6)\n";
break;
}
getch();
}while(opt != 6);
cout<<"Good Bye...";
flushall();
getch();
}//Ex. No. 2.4 Date : 16/08/04
//Dictionary implementation using arrays
//Sandra Johnson Reg. No. : 200431977
#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
#include<stdio.h>
//default constants
const minrow=5;
const rows=26;
const cols=30;
//base class arrays
class arrays
{
protected:
char** p; //pointer to a 2 dimensional char array
unsigned int size; //size of the array
public:
arrays(); //default constructor
arrays(unsigned int x); //user defined constructor
//stores the value at the index
void store(unsigned int index , char *value);
//returns the value at index
char *retrieve(unsigned int index);
unsigned int get_size(); //returns the size of the array
~arrays(); //destructor
void message_arr(int e); //displays the messages
};
arrays::arrays()
{
p=new char*[rows]; //allocates memory for rows
for(int i=0;i<rows;i++)
p[i]=new char[cols]; //allocates memory for columns
size=rows; //initializes the size
}
arrays::arrays(unsigned int x)
{
p=new char*[x]; //allocates memory for rows
for(int i=0;i<x;i++) //allocates memory for columns
p[i]=new char[cols];
size=x; //initializes the size
}
arrays::~arrays()
{
for(int i=0;i<size;i++)
delete[] p[i]; //deallocates the columns
delete[] p; //deallocates the rows
}
void arrays::store(unsigned int index, char *value)
{
//stores the value at the given index
if (index >= size) //cannot store beyond the size
{
message_arr(1);
return;
}
strcpy(*(p+index),value);
}
char *arrays::retrieve(unsigned int index)
{
//returns the value stored at the index
if (index >= size) //cannot retrieve beyond the size
{
message_arr(1);
return NULL;
}
return *(p+index);
}
unsigned int arrays::get_size()
{
return size; //returns the size of the array
}
void arrays::message_arr(int e)
{
//displays the messages given the message code
switch (e)
{
case 1:
cout<<"Illegal operation\n";
break;
default:
break;
};
}
//ordered list
class ordered_list:public arrays
{
protected:
unsigned int length ; //length of ordered list
public:
ordered_list():arrays() //default constructor
{
length=0;
}
ordered_list(unsigned int x):arrays(x) //overloaded constructor
{
length=0;
}
~ordered_list()
{
}
//inserts the value at the index and moving all the elements
//to the next location
void insert_ol(unsigned int index,char *value);
//deletes the value at the index
void delete_ol(unsigned int index);
//over writes the value at the index
void store_ol(unsigned int index,char *value);
//returns the value at the index
char *retrieve_ol(unsigned int index);
void list_ol(); //displays the ordered list
int search_loc(char *value); //searches the ordered list for
//the value & returns the index
int find_loc(char *value); //returns the correct location
//to insert the value into the list
unsigned int get_length(void); //returns the length
void message_ol(int e); //displays the message
};
void ordered_list::insert_ol(unsigned int index,char *value)
{
//inserts the value at the index and moving all the elements
//to the next location
int i;
if ((index > length) || (length == size))
{
message_ol(1);
return;
}
if (length != 0)
{ //cout<<"length = "<<length;getch();
// for(int i=(length-1);i>=index;i--)
i=(length-1);
while(i <= index)
{ //cout<<"i ="<<i<<"\t"<<"index = "<<index;
// getch();
store(i+1,retrieve(i));
i--;
}
}
store(index,value);
length++;
}
void ordered_list::delete_ol(unsigned int index)
{
//deletes the value given the index
if (index > length-1) //cannot delete beyond the length
{
message_ol(2);
return;
}
//move the values to the previous location
for(unsigned int i=index;i<length-1;i++)
store(i,retrieve(i+1));
length--;
}
void ordered_list::store_ol(unsigned int index,char *value)
{
//overwrites the value at the given location
if (index >length-1) //cannot store beyond the length
{
message_ol(3);
return;
}
store(index,value);
}
char *ordered_list::retrieve_ol(unsigned int index)
{
//returns the value given the index
if (index > length-1) //cannot retrieve beyond the length
{
message_ol(4);
return NULL;
}
return retrieve(index);
}
void ordered_list::list_ol()
{
//displays the ordered list
for(unsigned int i=0;i<length;i++)
cout<<retrieve(i)<<"\n";
}
int ordered_list::search_loc(char *value)
{
//search the value and return the location
for(int i=0;i<length;i++)
{
int cc=strcmp(value,retrieve(i));
if (cc == 0)
return i;
}
return -1; //return -1 if value is not found
}
int ordered_list::find_loc(char *value)
{
//returns the location to insert in an ordered list
for(unsigned int i=0;i<length;i++)
{
int ck=strcmp(value,retrieve(i));
if (ck <= 0) break;
}
return i;
}
unsigned int ordered_list::get_length(void)
{
return length; //returns the length of the ordered list
}
void ordered_list::message_ol(int e)
{ //displays the messages given the message code
switch(e)
{
case 1:
cout<<"Illegal insertion...\n";
break;
case 2:
cout<<"Illegal deletion...\n";
break;
case 3:
cout<<"Illegal store operation...\n";
break;
case 4:
cout<<"Illegal retrieval...\n";
break;
default:
break;
};
}It looks like you used to 'break' but now just return 1. I take it that the break failed as well?
I'd look more closely at the dictionary destructor. It sure looks simple, but maybe something there has gone astray.
There's no return from main, and main doesn't have the argv[], argc parameters; is that ok in turbo C?
Doesn't turbo C have a debugger you could set a breakpoint at the case for 6 and step line by line (step IN) to see where it fails?
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