#include <iostream>
#include <iomanip>
#include <conio.h>
#include <windows.h>


class cChain    //just a random chain class that is 24 bytes big
{
 public:
 cChain(): prev(0), next(0) {}; //reset pointers
 cChain * prev;                 //pointer to previous element
 cChain * next;                 //pointer to next element
 int a;  //an integer just to fill the space
 int b;  //an integer just to fill the space
 int c;  //an integer just to fill the space
 int d;  //an integer just to fill the space
};

void SetColor(int dwFront, int dwBack); //this sets color of the text (for Failed)

using namespace std;

int main(int argc, char *argv[])
{
  unsigned int iRamAmount = 0;  //defines how much ram (mb) will be tested
  double dLoops = 0;            //how many loops have to be done
  cChain Chain;                 //our Chain of dynamically allocated variables
  cChain * Current = &Chain;    //pointer to a current element of the chain
  int iFailCount = 0;           //how many times did the test fail?
  double x;                     //counter used when allocating memory      
  double y;                     //counter used when freeing memory  
  int iCurPercent = 0;          //determines which percent we currently are
  bool bFail = 0;               //did something fail?
 
  
  cout << "Enter amount of RAM to be tested (MB): "; //asks the user
  cin >> iRamAmount;                                 //gets the user's answer
  cout << endl;
  
  if(iRamAmount <= 0) //if somebody put a value smaller/equal to zero...
    {
     cout << "ERROR: The value must be greater than zero!" << endl; //call him and idiot
     system("PAUSE");	 //wait
     return 0;     //and quit
    }
    
    
  dLoops = (double)iRamAmount*1024*1024 / sizeof(cChain);  //calculates how many times the loop has to be done
  
  while (kbhit()) getch();   // Empties buffer      
  
  cout << "Size of allocated block: " << sizeof(cChain) << " bytes." << endl;
  cout << "Memory will be allcoated " << setiosflags(ios::fixed) << setprecision(0) << dLoops << " times." << endl;
 
  cout << "Press any key to begin" << endl << endl;
  
  getch();
  
  for(x = 0; x < dLoops; x++)
    {
     Current->next = new cChain;  //dynamically allocate more memory!
     if(Current->next != 0)       //if it did not fail
          {
           Current->next->prev = Current;    //set the previous pointer of the next chain element to current chain element
           Current = Current->next;          //set current pointer to the next chain element
          }
     else                         //if allocation failed...
          {                   
          iFailCount++;           //increment fail count
          bFail = 1;              //set bFailed
          }
          
     if(dLoops/100*iCurPercent <= x+1)      //if we got to the next percent...
          {
          cout << "\r" << setw(3) << (int)((x+1)/dLoops * 100) << "% ; Fail count: " << setw(5) << iFailCount;   
          //the above simply displays nicely formatted percentage and fail count
          if(bFail)          //if allocation failed
                    {          
                     SetColor(4,0);
                     cout << "\tFailed!"; //display a red warning
                     SetColor(7,0);   
                    }          
          iCurPercent++;                  //increase the next percent we're looking for
          }

     if(kbhit())                    //if someone pressed something
          {
          cout << endl <<"Aborted" << endl;     //say abort
          getch();                              //empty the buffer
          break;                                //break the loop
          }
    }
  
  cout << endl << endl << "Freeing memory..." << endl << endl; //inform the user

  iCurPercent = 0;  //reset current percent since we're starting again...
  bFail = 0;        //reset bFail since we're starting again...
  
  
  for(y = 0; y < x; y++)   //do this loop as many times as we have allocated memory
    {
     if(Current->prev != 0)          //if the previous pointer is not 0 (shouldn't be)
          {
           Current = Current->prev;  //set current pointer to the previous element of chain
           delete Current->next;     //delete next element of chain (we're moving back)
          }
     else                            //if the previous pointer is 0 
          {
          bFail = 1;                 //something went wrong...
          }
        
     if(x/100*iCurPercent <= (y+1))   //if we got to the next percent...       
          {
          cout << "\r" << setw(3) << (int)((y+1)/x * 100) << "% ; Fail count: " << setw(5) << iFailCount;   
          //the above simply displays nicely formatted percentage and fail count
          if(bFail)          //if the previous pointer was 0 (shouldn't be)
                    {
                     SetColor(4,0);
                     cout << "\tPrevious pointer is 0"; //inform the user
                     SetColor(7,0);   
                    }
                    
          iCurPercent++;     //increment current percent                 
          }     

     if(kbhit())                    //if someone pressed something
          {
          cout << endl <<"Aborted" << endl;     //say abort
          getch();                              //empty the buffer
          break;                                //break the loop
          }          
    }  
    
  cout << endl << endl << "Test finished.\nMemory Tested: " << x/1024/1024 * sizeof(cChain) << " MB.\nFail count: " << iFailCount << endl;
  //inform user
  system("PAUSE");	 //wait
  return 0; // go home!
}



void SetColor(int dwFront, int dwBack)
{
	SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 16 * dwBack + dwFront);
}

#define SIZE 1024 class cChain    { public: cChain(): prev(0), next(0) {}; //reset pointers cChain * prev;                 //pointer to previous element cChain * next;                 //pointer to next element int a[SIZE];  //continuous memory block to fill the space};