Reverse Output (Stack)

[silicon]

Hi everyone, I've been taking a class on cprogramming and have been successful up thus far. I am now learning about stacks and am having tremendous problems. I've written a program that will calculate the prime factors of numbers. The only problem is that I needed to reverse the output as show in the example below
e.g. Prime factors of #
1
2
3
4

need printout to read
4
3
2
1

I understand the concept in which the output will first be stored in an array [1,2,3,4] but am not entirely sure on how to retreive it without making the program really long. I know about pop functions but have only used this with push empty and full functions in class. I am just having problems on trying to figure out how to implement it here.
I've tested my prime factorization program by itself and I know it works but when I try to integrate it into the stack I get numerous errors and I am not sure if I am on the right track
Please let me know if you have any suggestions. I feel as if I am close but am started to get frustrated because it feels as if I am missing something small
Any help will be greatly appreciated

Thanks in advance
Sean

#include <iostream.h>
const int STACK_MAX= 20;
typedef int StackElement;

class Stack
 {
  private:
   StackElement StackArray[STACK_MAX];
   int StackTop;

 public:
  bool empty();
  int primefactor(int number);
  bool full( );
    bool isprime(int number);
    void push(const StackElement & value);
    void pop();
  int top();
  void display();

    Stack::Stack()                          //Constructor
   {
    StackTop=-1;

   }

  Stack::primefactor(int number)
{
   bool isPrime = isprime();
   int prime = number;
   int i = 2, j;
   double squareroot = sqrt(static_cast<double>(number));
  int count = 0;
   cout << "The prime factorization of the number " << number << " is:" << endl;
  if(isPrime)
      cout << space << number << " is a prime number." << endl;
   else {
      while((prime > 0) && (i <= number)) {
         if((prime % i) == 0) {
        count++;
        for(j = 0; j < count; j++)
          cout << space;
            cout << i << " is a factor" << endl;
            prime /= i;
      } else         
           i++;
      }
 return true;
}


   void Stack::push(const StackElement & value)   //Add value to the Stack
   {
    if(StackTop<STACK_MAX-1)                     //If Stack is not full add element
      {
       ++StackTop;
       StackArray[StackTop]=value;
      }
    else
     cout<<"Stack is full. \n";
   }



  inline bool Stack::empty() const       //Check for emptyness
   {
    return(StackTop==-1);
   }

}

   
    bool isprime(int number)
{
   int i;
   
   for(i = 2; i < number; i++) {
      if((number % i) == 0)
         return false;
   }
   


    StackElement Stack::top()const     //function to retireve value at top of Stack
     {
      if(StackTop>=0)                   //If Stack is not empty perform task
       return StackArray[StackTop];
      else
      cout<<"Stack is empty\n";
      }

     void Stack::pop()         //Function to discard value at top of Stack
      {
       if(StackTop>=0)        //If Stack is not empty perform task
        StackTop--;
       else
       cout<<"Stack is empty\n";
      }

   void Stack::display()     //Function to write the entire stack
    {
     for(int i=StackTop;i>=0;i--)
     cout<<StackArray[i]<<endl;
    }
               
int main()
 {
    Stack factors;
  int number;
   
  cout << "Enter a number > 1000 ";
   cin >> number;

  
   
      factors.primefactor();
      factors.top();
      factors.pop();
      factors.display();
    };

[silicon]

This is a copy of my prime number code before implementing the stack

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

const string SPACE_STR = "   ";

void prime_factor(int number);
bool is_prime(int number);

int main() {
   int number;

   cout << "Enter a number > 1000 -> ";
   cin >> number;

   prime_factor(number);

   return 0;
}

// Function I need help with.

void prime_factor(int number)
{
   bool isPrime = is_prime(number);
   int prime = number;
   int i = 2, j;
   double squareRoot = sqrt(static_cast<double>(number));
	int count = 0;
   
   cout << "The prime factorization of the number " << number << " is:" << endl;
	
	if(isPrime)
      cout << SPACE_STR << number << " is a prime number." << endl;
   else {
      while((prime > 0) && (i <= number)) {
         if((prime % i) == 0) {
				count++;
				for(j = 0; j < count; j++)
					cout << SPACE_STR;
            cout << i << " is a factor" << endl;
            prime /= i;
			} else         
         	i++;
      }
   }
}

bool is_prime(int number)
{
   int i;
   
   for(i = 2; i < number; i++) {
      if((number % i) == 0)
         return false;
   }
   
   return true;
}

[Chainsaw]

Why not just run the original program's loop down from sqrt(number) down to 2, rather than go up? Yes, you'd have to check i with is_prime(), but the numbers would come out in the right order.

If you really want to use a stack, there are standard stack classes, but you could do it without a class very simply too. If it were me, I'd probably do a simple simple simple class:

static const int MAX_STACK = 1000;
class AnIntStack
{
public:
    AnIntStack()    { m_top = 0; }
    void Push(int n) { if (m_top < MAX_STACK) m_stack[m_top++] = n; }
    int Pop(int n) { if (m_top > 0) return m_stack[--m_top]; else return 0; }
    bool IsEmpty() const { return (m_top <= 0); }
protected:
int m_stack[MAX_STACK];
int m_top;
};

and then in your *original* code where you did the output you would say something like mystack.Push(i); and in the main you would have a final loop saying something like "while (!mystack.IsEmpty()) <print element mystack.Pop()>

Is that what you were after?

[silicon]

Hello thanks for the tips. I've rewritten most of my code and came up with what's below. I am receiving 3 errors so I am unable to troubleshoot or see if there will be errors in the output. I believe that it is definitely close now. I know that the errors are with my function calls at the end but I thought that this was the method used for calling them.

Example: in the code (w/o stack) if I enter 36 It should return the prime factors
2 is a factor
2 ""
3 ""
3 ""

With the stack implemented now it is supposed to now return
3 is a factor
3 ""
2 ""
2 ""

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

const string SPACE_STR = "   ";

static const int MAX_CAPACITY = 1000;
class Stack
{
public:
    Stack()    { top = 0; }
    void primefactor (int number);
	bool is_prime(int number);
	void Push(int number) ;
    int Pop(int number) ;
  
	
private:
int arraystack[MAX_CAPACITY];
int top;
};

// Function I need help with.

void Stack::primefactor(int number)
{
   bool isPrime = is_prime(number);
   int prime = number;
   int i = 2, j;
   double squareRoot = sqrt(static_cast<double>(number));
	int count = 0;
   
   cout << "The prime factorization of the number " << number << " is:" << endl;
	
	if(isPrime)
      cout << SPACE_STR << number << " is a prime number." << endl;
   else {
      while((prime > 0) && (i <= number)) {
         if((prime % i) == 0) {
				count++;
				for(j = 0; j < count; j++)
					cout << SPACE_STR;
            cout << i << " is a factor" << endl;
            prime /= i;
			} else         
         	i++;
      }
   }
}

bool Stack::is_prime (int number)
{
   int i;
   
   for(i = 2; i < number; i++) {
      if((number % i) == 0)
         return false;
   }
   
   return true;
}


void Stack::Push(int number)
{ if (top < MAX_CAPACITY) 
	arraystack[top++] = number; 

}
int Stack::Pop(int number) 
 { if (top > 0) return arraystack[--top]; else return 0; 
 }


int main() {
   int number;

   cout << "Enter a number > 1000 -> ";
   cin >> number;

   Stack::primefactor();
   Stack::Push();
   Stack::Pop();
   return 0;
}

[silicon]

Hi, I have completed the code so and am now able to compile but for some reason it will not take the output and reverse it

example prime factors of 100
2
2
5
5

I am still trying to get it to print
5
5
2
2

It seems as if everything is written correctly but the output has not changed :sad:

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

const string SPACE_STR = "   ";

static const int MAX_CAPACITY = 1000;
class Stack
{
public:
    Stack()    { top = 0; }
    void primefactor (int number);
	bool is_prime(int number);
	void Push(int number) ;
    int Pop(int number) ;
  
	
private:
int arraystack[MAX_CAPACITY];
int top;
};

// Function I need help with.

void Stack::primefactor(int number)
{
   bool isPrime = is_prime(number);
   int prime = number;
   int i = 2, j;
   double squareRoot = sqrt(static_cast<double>(number));
	int count = 0;
   
   cout << "The prime factorization of the number " << number << " is:" << endl;
	
	if(isPrime)
      cout << SPACE_STR << number << " is a prime number." << endl;
   else {
      while((prime > 0) && (i <= number)) {
         if((prime % i) == 0) {
				count++;
				for(j = 0; j < count; j++)
					cout << SPACE_STR;
            cout << i << " is a factor" << endl;
            prime /= i;
			} else         
         	i++;
      }
   }
}

bool Stack::is_prime (int number)
{
   int i;
   
   for(i = 2; i < number; i++) {
      if((number % i) == 0)
         return false;
   }
   
   return true;
}


void Stack::Push(int number)
{ if (top < MAX_CAPACITY) 
	arraystack[top++] = number; 

}
int Stack::Pop(int number) 
 { if (top > 0) return arraystack[--top]; else return 0; 
 }


int main() {
   Stack mystack;
	int number;

   cout << "Enter a number > 1000 -> ";
   cin >> number;

	mystack.primefactor(number);
	mystack.Push(number);
	mystack.Pop(number);
   

   return 0;
}

[Chainsaw]

In your code, where you have:

cout << i << " is a factor" << endl;

That's where you should INSTEAD say:

mystack.Push(i);

So, now it puts things onto the stack instead of printing them. In your main routine, where you now do Push and Pop, you instead need a loop that pops off each pushed number and prints that number out. something like:

int i;
while (i = mystack.Pop())
    cout << i << " is a factor" << endl;