I just finished working on this program but from the beginning I noticed that it was somehow not printing out everything it was supposed to.
It’s needs to print the integers in a stack beginning from the top first and then do it again beginning from the bottom.
It prints the top to bottom correctly, but for some reason it only prints the very bottom number on the bottom to top.
for example if a stack contains the integers 1, 2, 3, 4, 5, 6,
where 1 is at the bottom of the stack and 6 is the top number.
the program should print the following:
Top { 6 5 4 3 2 1 } Bottom Bottom { 1 2 3 4 5 6 } Top
but it prints the following:
Top { 6 5 4 3 2 1 } Bottom Bottom { 1 } Top
here is the print function:
void Print() const
// Prints stack contents to stdout in both top-to-bottom and bottom-to-top order
{
Node* temp = topPtr;
cout << "Top { ";
// Forward print
while (temp != NULL)
{
cout << temp->data << " ";
if (temp->next == NULL)
break;
temp = temp->next;
}
cout << "} Bottom Bottom { ";
// Reverse print
while (temp != NULL)
{
cout << temp->data << " ";
temp = temp->previous;
}
cout << "} Top" << endl;
} // End Print()
}; // End Class Stack
and If you need any further reference here is the main()
#include <iostream>
#include <fstream>
#include <new>
#include <cstddef>
#include "stack.h"
using namespace std;
int main(int argc, char* argv[])
{
ifstream inputs; // Input file for commands
char op; // Hold operation and optional char input
int value; // Value input from file
string comment; // Holds comment from file
Stack* sPtr = NULL; // Will point to stack object
// Output usage message if one input file name is not provided
if (argc != 2)
{
cout << "Usage:\n project03 <inputfile>\n";
return 1;
}
// Attempt to open input file -- terminate if file does not open
inputs.open(argv[1]);
if (!inputs)
{
cout << "Error - unable to open input file" << endl;
return 1;
}
// Input and echo header comment from file
getline(inputs, comment); // Input and echo the comment appearing in the test file
cout << endl << '#' << comment << endl;
// Process commands from input file
inputs >> op; // Attempt to input first command
while (inputs)
{
switch (op) // Process operation input from file
{
case '#': // Test file comment
getline(inputs, comment); // Input and echo the comment appearing in the test file
cout << '#' << comment << endl;
break;
case 'c': // Constructor
cout << endl << "Stack( )";
try
{
sPtr = new Stack( ); // Attempt to create an empty stack object
cout << " -- Successful" << endl;
}
catch ( std::bad_alloc )
{
cout << "Failed : Terminating now..." << endl;
return 1;
}
break;
case '+': // Push
inputs >> value;
cout << "Push(" << value << ")";
try
{
sPtr->Push(value);
cout << " -- successful";
}
catch (StackFull)
{
cout << " -- Failed Full Stack";
}
cout << endl;
break;
case '-': // Pop
cout << "Pop() -- ";
try
{
sPtr->Pop();
cout << "successful";
}
catch (StackEmpty)
{
cout << "Failed Empty Stack";
}
cout << endl;
break;
case 'f': // IsFull
cout << "IsFull() -- ";
try
{
if (sPtr->IsFull())
cout << "true";
else
cout << "false";
}
catch ( ... )
{
cout << "operation failed";
}
cout << endl;
break;
case 'e': // IsEmpty
cout << "IsEmpty() -- ";
try
{
if (sPtr->IsEmpty())
cout << "true";
else
cout << "false";
}
catch ( ... )
{
cout << "operation failed";
}
cout << endl;
break;
case 'm': // Make Empty
sPtr->MakeEmpty();
cout << "MakeEmpty()" << endl;
break;
case 'p': // Print Stack
cout << "Print() -- ";
sPtr->Print();
break;
case 't': // Top of Stack
try
{
cout << "Top() -- " << sPtr->Top() << endl;
}
catch (StackEmpty)
{
cout << "Top() -- Failed Empty Stack" << endl;
}
break;
case '>': // Max value within Stack
try
{
cout << "Max() -- " << sPtr->Max() << endl;
}
catch (StackEmpty)
{
cout << "Max() -- Failed Empty Stack" << endl;
}
break;
case '<': // Min value within Stack
try
{
cout << "Min() -- " << sPtr->Min() << endl;
}
catch (StackEmpty)
{
cout << "Min() -- Failed Empty Stack" << endl;
}
break;
case '?': // Peek(n) Stack
inputs >> value;
try
{
cout << "Peek(" << value << ") -- " << sPtr->Peek(value) << endl;
}
catch (StackInvalidPeek)
{
cout << "Peek(" << value << ") -- Failed Invalid Peek" << endl;
}
break;
case 's': // Size of Stack
cout << "Size() -- " << sPtr->Size() << endl;
break;
case 'd': // Destructor
delete sPtr;
sPtr = NULL;
cout << "~Stack()" << endl << endl;
break;
default: // Error
cout << "Error - unrecognized operation '" << op << "'" << endl;
cout << "Terminating now..." << endl;
return 1;
break;
}
inputs >> op; // Attempt to input next command
}
return 0;
} // End main()
and here is header file for stack.cpp (stack.h)
//
// stack.h
//
// Specification file for Stack class, a stack of integers implemented
// using doubly-linked nodes.
//
// ***** DO NOT MODIFY THIS FILE *****
//
#include <iostream>
using namespace std;
#ifndef STACK_H
#define STACK_H
class StackEmpty { /* No Code */ };
// StackEmpty exception class - throw an object of this type when stack is empty
// Hint: there is no code for exception classes
class StackFull { /* No Code */ };
// StackFull exception class - throw an object of this type when stack is full
class StackInvalidPeek { /* No Code */ };
// StackInvalidPeek exception class - throw an object of this type when invalid peek position is used
struct Node // Node data type for storing a single stack entry along with pointers to
{ // neighboring entries (previous and next) in the stack
Node* previous; // Member variable that holds the address of the predessor node in the stack sequence
Node* next; // Member variable that holds the address of the successor node in the stack sequence
int data; // Member variable that holds the data value
};
class Stack // Implements stack of integers ADT using doubly-linked sequence of nodes
{
private:
Node* topPtr; // Points to the top node on the stack array
public:
Stack(); // Default constructor initializes empty stack
~Stack(); // Destructor deallocates all nodes from stack
// Must not create a memory leak
void Push(int n); // Pushes integer n onto top of stack.
// If unable to push, throws StackFull exception.
void Pop(); // Removes top integer from stack
// If stack is already empty, throws StackEmpty exception
bool IsEmpty() const; // Returns true if stack is empty; false otherwise
bool IsFull() const; // Returns true if stack is full; false otherwise
void MakeEmpty(); // Removes all nodes from stack leaving an empty, but usable stack
// Must not create a memory leak
int Top() const; // Returns value of top integer on stack WITHOUT modifying the stack
// If stack is empty, throws StackEmpty exception
int Size() const; // Returns number of items on stack WITHOUT modifying the stack
int Max() const; // Returns value of largest integer within stack WITHOUT modifying the stack
// If stack is empty, throws StackEmpty
int Min() const; // Returns value of smallest integer within stack WITHOUT modifying the stack
// If stack is empty, throws StackEmpty
int Peek( int n) const; // Returns stack value n levels down from top of stack. Peek(0) = Top()
// If position n does not exist, throws StackInvalidPeek
. ./******* DO NOT MODIFY ANY OF THE CODE FOR PRINT() *******/
/****** DO NOT PLACE A COPY OF PRINT() CODE IN STACK.CPP!!! *******/
void Print() const
// Prints stack contents to stdout in both top-to-bottom and bottom-to-top order
{
Node* temp = topPtr;
cout << "Top { ";
// Forward print
while (temp != NULL)
{
cout << temp->data << " ";
if (temp->next == NULL)
break;
temp = temp->next;
}
cout << "} Bottom Bottom { ";
// Reverse print
while (temp != NULL)
{
cout << temp->data << " ";
temp = temp->previous;
}
cout << "} Top" << endl;
} // End Print()
}; // End Class Stack
#endif
and finally here is stack.cpp which is the file I created the rest was given.
//
// stack.cpp
//
//
// Created by Otapia on 9/19/11.
// Copyright 2011 __MyCompanyName__. All rights reserved.
//
#include <iostream>
#include <new>
#include "stack.h"
Stack::Stack() // Default constructor initializes empty stack
{
topPtr = NULL;
}
Stack::~Stack() // Destructor deallocates all nodes from stack
// Must not create a memory leak
{
Node* tempPtr;
while ( topPtr != NULL )
{
tempPtr = topPtr;
topPtr = topPtr->next;
delete tempPtr;
}
}
void Stack::Push(int n) // Pushes integer n onto top of stack.
// If unable to push, throws StackFull exception.
{
if(!IsFull())
{
Node* tempPtr = new Node;
tempPtr->data = n;
tempPtr->next = topPtr;
topPtr = tempPtr;
}
else
throw IsFull();
}
void Stack::Pop() // Removes top integer from stack
// If stack is already empty, throws StackEmpty exception
{
if (!IsEmpty())
{
Node* tempPtr;
tempPtr = topPtr;
topPtr = topPtr->next;
delete tempPtr;
}
else
throw StackEmpty();
}
bool Stack::IsEmpty() const // Returns true if stack is empty; false otherwise
{
return(topPtr == NULL);
}
bool Stack::IsFull() const // Returns true if stack is full; false otherwise
{
Node* location;
try
{
location = new Node;
delete location;
return false;
}
catch(std::bad_alloc)
{return true; }
}
void Stack::MakeEmpty() // Removes all nodes from stack leaving an empty, but usable stack
// Must not create memory leak
{
Node* tempPtr;
while ( topPtr != NULL ) {
tempPtr = topPtr;
topPtr = topPtr->next;
delete tempPtr;
}
topPtr = NULL;
}
int Stack::Top() const // Returns value of top integer on stack WITHOUT modifying the stack
{
if(!IsEmpty())
return topPtr->data;
throw StackEmpty();
}
int Stack::Size() const // Returns number of items on stack WITHOUT modifying the stack
{
Node* temp = topPtr;
int count = 0;
while (temp != NULL)
{
temp = temp->next;
count ++;
}
return count;
}
int Stack::Max() const // Returns value of largest integer within stack WITHOUT modifying the stack
// If stack is empty, throws StackEmpty
{
int max = 0;
int n;
Node* temp = topPtr;
if(!IsEmpty())
{
while(temp != NULL)
{
n = temp->data;
if(n > max)
{
max = n;
}
temp = temp->next;
}
return max;}
else
throw StackEmpty();
}
int Stack::Min() const // Returns value of smallest integer within stack WITHOUT modifying the stack
// If stack is empty, throws StackEmpty
{int min = 100;
int n;
Node* temp = topPtr;
if(!IsEmpty())
{
while(temp != NULL)
{
n = temp->data;
if(n < min)
{
min = n;
}
temp = temp->next;
}
return min;}
else
throw StackEmpty();
}
int Stack::Peek(int n) const // Returns stack value n levels down from top of stack. Peek(0) = Top()
// If position n does not exist, throws StackInvalidPeek
{
int num = 0;
int x = 0;
Node* temp = topPtr;
if(!IsEmpty())
{
while(temp != NULL)
{
if (x >= n || temp->next == NULL)
break;
temp = temp->next;
x++;
}
if (n <= x)
{
num = temp->data;
}
else throw StackInvalidPeek();
}
else
throw StackInvalidPeek();
return num;
}
Simple.
From your problem description, and the error’d code, I’d assume
temp->previousis incorrect. I assume this gets set in some sort ofpushfunction.You never set
previous, so it’s left as some unspecified value (of zero). Also,previousis not set or checked anywhere in your cpp file. It should be set here, although really doesn’t need to be anywhere else.Lastly,
throw IsFull()is a heck of an exception. You probably didn’t mean tothrowtheboolresult of a function call.