Problem adding words to a stack

tpoole00 (3)
So far i have
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#include<iostream>
#include<cstdlib>
#include<fstream>
#include<math.h>

using namespace std;
                            
void displayMenu();             //menu

void push(char);                //push (option 1)
void pop();                     //pop (option 2)
void display(char);                 //display (option 3)
void exit();                    //exit (option 4)

bool isEmpty();                 //funtion to check if stack is empty

int* stack = NULL;
int top = 0;
int size = 0;
 
void displayMenu()          //the menu that is displayed
{
    cout << "\nEnter either a 1, 2, 3, or 4: " << endl << endl;
    cout << "1. Push <string>" << endl;
    cout << "2. Pop" << endl;
    cout << "3. Display" << endl;
    cout << "4. Exit" << endl << endl;
    
}//end displayMenu

void push(char* word)
{
     stack[top] = *word;    //PROBLEM HERE <--
     size=size+1;
     cout << "pushed '" << word << "'" << endl;
}

void display()
{
     if(isEmpty())                                  //runs function (isempty) to see if stack is empty
      cout << "\nThe stack is empty. There is nothing to print." << endl;
    else
    {
      cout << "\nThe stack contains: " << endl;
      cout << *(stack) << endl;
     }
}
void pop()
{
}
bool isEmpty()            //function to check if stack is empty
{
     if(size == 0)
       return true;       //true if empty
     else
       return false;      //false if not empty
}//end isEmpty

int main()        //start of main function
{
    char choice;
    int number;
    cout << "Welcome to the CSC 130 Dynamic Stack Program!" << endl;
    cout << "Make a choice from one of the 4 options below." << endl;
    do
    {
        displayMenu();
        cin.get(choice);
        switch(choice)
        {
          case '1':
               cout << "\nEnter the word you would like to push: ";
               char word[80];
               cin >> word;
               push(word);
               break;
          case '2':
               pop();  //runs function pop
               break;
          case '3':
               display();     //runs function display
               break;
          case '4':
               exit(0);  //terminates program
          
          default:
               cout << "\nYou entered an invalid choice. Try again." << endl;
       }//end switch
      cin.ignore();
    }while(true);

  // system("pause");
   return 0;
}//end main


the problem is I dont know how to add words to my array, it might be something silly but i dont recall what I am suppose to do here
andywestken (4094)
stack[top] = *word; //PROBLEM HERE <--

#1 As word is a char*, dereferencing it's given you a char; the first char in your string.

#2 Your stack (pointer) is (a) pointing nowhere (so there's no memory to store your string) and is (b) the wrong data type (you are wanting to store words??)

I would consider using an array of char buffers for your stack to start with, and worry about dynamic memory allocation later on, if needed.

I can also see a number of other issues, including function signatures, confusion between top/size, etc

Also, you should try to avoid using exit() to quit a program. I would expect its use to limited to error handling. Try using a loop control variable instead and have the exit case change its value to exit the loop.
Last edited on
tpoole00 (3)
ok i changed it around to use a string but for some reason program skips the problem line completely and I dont understand why

heres the new code

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#include <iostream>
#include <cstdlib>
#include <fstream>
#include <math.h>
#include <string>

using namespace std;
                            
void displayMenu();             //menu

void push(char);                //push (option 1)
void pop();                     //pop (option 2)
void display(char);                 //display (option 3)
void exit();                    //exit (option 4)

bool isEmpty();                 //funtion to check if stack is empty

string sk;
int size = 0;
 
void displayMenu()          //the menu that is displayed
{
    cout << "\nEnter either a 1, 2, 3, or 4: " << endl << endl;
    cout << "1. Push <string>" << endl;
    cout << "2. Pop" << endl;
    cout << "3. Display" << endl;
    cout << "4. Exit" << endl << endl;
    
}//end displayMenu

void push()
{
     
     cout << "\nEnter the word you would like to push: ";
     getline (cin,sk);    //PROBLEM HERE <---
     size=size+1;
     cout << "Pushed '" << sk << "'" << endl;
}

void display()
{
     if(isEmpty())                                  //runs function (isempty) to see if stack is empty
      cout << "\nThe stack is empty. There is nothing to print." << endl;
    else
    {
      cout << "\nThe stack contains: " << endl;
      cout << sk << endl;
     }
}
void pop()
{
}
bool isEmpty()            //function to check if stack is empty
{
     if(size == 0)
       return true;       //true if empty
     else
       return false;      //false if not empty
}//end isEmpty

int main()        //start of main function
{
    char choice;
    int number;
    cout << "Welcome to the CSC 130 Dynamic Stack Program!" << endl;
    cout << "Make a choice from one of the 4 options below." << endl;
    do
    {
        displayMenu();
        cin.get(choice);
        switch(choice)
        {
          case '1':
               push();
               break;
          case '2':
               pop();  //runs function pop
               break;
          case '3':
               display();     //runs function display
               break;
          case '4':
               exit(0);  //terminates program
          
          default:
               cout << "\nYou entered an invalid choice. Try again." << endl;
       }//end switch
      cin.ignore();
    }while(true);

  // system("pause");
   return 0;
}//end main


and i know i should try to aviod using exit() but for this program I dont think it matters
Last edited on
andywestken (4094)
Now you're just providing space for a single string. Just enough for a "stack" of one string?
Last edited on
viliml (791)
what about:
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#include <iostream>
#include <cstdlib>
#include <fstream>
#include <math.h>
#include <string>

using namespace std;
                            
void displayMenu();             //menu

void push(char);                //push (option 1)
void pop();                     //pop (option 2)
void display(char);                 //display (option 3)
void exit();                    //exit (option 4)

bool isEmpty();                 //funtion to check if stack is empty

string sk;
int size = 0;
string* stack=new string[1];
 
void displayMenu()          //the menu that is displayed
{
    cout << "\nEnter either a 1, 2, 3, or 4: " << endl << endl;
    cout << "1. Push <string>" << endl;
    cout << "2. Pop" << endl;
    cout << "3. Display" << endl;
    cout << "4. Exit" << endl << endl;
    
}//end displayMenu

void push()
{
     
     cout << "\nEnter the word you would like to push: ";
     getline (cin,sk);    //PROBLEM HERE <---
     stack[size]=sk;
     ++size;
     stack=new (stack) string[size];
     cout << "Pushed '" << sk << "'" << endl;
}

void display()
{
     if(isEmpty())                                  //runs function (isempty) to see if stack is empty
      cout << "\nThe stack is empty. There is nothing to print." << endl;
    else
    {
      cout << "\nThe stack contains: " << endl;
      cout << sk << endl;
     }
}
void pop()
{
      --size;
      cout<<"popped '"<<stack[size]<<"'";
      stack=new (stack) string[size];
}
bool isEmpty()            //function to check if stack is empty
{
     if(size == 0)
       return true;       //true if empty
     else
       return false;      //false if not empty
}//end isEmpty

int main()        //start of main function
{
    char choice;
    int number;
    cout << "Welcome to the CSC 130 Dynamic Stack Program!" << endl;
    cout << "Make a choice from one of the 4 options below." << endl;
    do
    {
        displayMenu();
        cin.get(choice);
        switch(choice)
        {
          case '1':
               push();
               break;
          case '2':
               pop();  //runs function pop
               break;
          case '3':
               display();     //runs function display
               break;
          case '4':
               exit(0);  //terminates program
          
          default:
               cout << "\nYou entered an invalid choice. Try again." << endl;
       }//end switch
      cin.ignore();
    }while(true);

  // system("pause");
   return 0;
}//end main
?
andywestken (4094)
;-)

This is worse than your first version.

Rather than abusing placement new, I would try using an array for your stack.
viliml (791)
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#include <iostream>
#include <cstdlib>
#include <fstream>
#include <math.h>
#include <string>

using namespace std;
                            
void displayMenu();             //menu

void push(char);                //push (option 1)
void pop();                     //pop (option 2)
void display(char);                 //display (option 3)
void exit();                    //exit (option 4)

bool isEmpty();                 //funtion to check if stack is empty

string sk;
int size = 0;
const in maxsize=100;
string stack[maxsize];
 
void displayMenu()          //the menu that is displayed
{
    cout << "\nEnter either a 1, 2, 3, or 4: " << endl << endl;
    cout << "1. Push <string>" << endl;
    cout << "2. Pop" << endl;
    cout << "3. Display" << endl;
    cout << "4. Exit" << endl << endl;
    
}//end displayMenu

void push()
{
     
     cout << "\nEnter the word you would like to push: ";
     getline (cin,sk);    //PROBLEM HERE <---
     stack[size]=sk;
     ++size;
     cout << "Pushed '" << sk << "'" << endl;
}

void display()
{
     if(isEmpty())                                  //runs function (isempty) to see if stack is empty
      cout << "\nThe stack is empty. There is nothing to print." << endl;
    else
    {
      cout << "\nThe stack contains: " << endl;
      cout << sk << endl;
     }
}
void pop()
{
      delete stack+size;
      --size;
      cout<<"popped '"<<stack[size]<<"'";
}
bool isEmpty()            //function to check if stack is empty
{
     if(size == 0)
       return true;       //true if empty
     else
       return false;      //false if not empty
}//end isEmpty

int main()        //start of main function
{
    char choice;
    int number;
    cout << "Welcome to the CSC 130 Dynamic Stack Program!" << endl;
    cout << "Make a choice from one of the 4 options below." << endl;
    do
    {
        displayMenu();
        cin.get(choice);
        switch(choice)
        {
          case '1':
               push();
               break;
          case '2':
               pop();  //runs function pop
               break;
          case '3':
               display();     //runs function display
               break;
          case '4':
               exit(0);  //terminates program
          
          default:
               cout << "\nYou entered an invalid choice. Try again." << endl;
       }//end switch
      cin.ignore();
    }while(true);

  // system("pause");
   return 0;
}//end main

better?
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