Question

#include "stdafx.h"
#include <iostream>
#include <vector>
#include <cassert>

using namespace std;

// function prototypes
int loadDisk(vector<int> &firstPeg, int numDisks);
void printPeg(vector<int> &peg);
int hanoi(struct pegType &startPeg, struct pegType &swapPeg, struct pegType &endPeg, int numDisk);
void moveDisk(struct pegType &startPeg, struct pegType &endPeg);

struct pegType
{
   vector <int> diskStack;
   int name;
};

int main()
{
   int numDisk = 7;
   int i;

   pegType peg1, peg2, peg3;

   peg1.name = 1;
   peg2.name = 2;
   peg3.name = 3;

   cout << "-------------------------------" << endl;
   cout << " Towers of Hanoi " << endl;
   cout << "-------------------------------" << endl << endl;

   loadDisk(peg1.diskStack, numDisk); // Load Peg 1 with 7 disks
  
   cout << "\npeg1 has " << peg1.diskStack.size() << " discs";
   cout << "\npeg2 has 0" << " discs";
   cout << "\npeg3 has 0" << " discs" << endl;
  
   cout << "Starting Condition: " << endl << endl;
   printPeg(peg1.diskStack);
   printPeg(peg2.diskStack);
   printPeg(peg3.diskStack);

   int total = hanoi(peg1, peg3, peg2, numDisk);

   cout << "End Condition: " << endl << endl;
   printPeg(peg1.diskStack);
   printPeg(peg2.diskStack);
   printPeg(peg3.diskStack);

   cout << "A stack of " << numDisk << " can be transferred in " << total << " moves!" << endl;
  
   system("pause");
   return 0;
}

// function definitions

int loadDisk(vector<int> &pegType, int numDisks)
{
   int i;

   for (i = numDisks; i > 0; i--)
   {
       pegType.push_back(i);
   }
  
   return i;
}

void printPeg(vector<int> &peg)
{
   for (unsigned int i = 0; i < peg.size(); i++)
   {
       cout << peg[i] << endl;
   }
}

int hanoi(pegType &startPeg, pegType &swapPeg, pegType &endPeg, int numDisk)
{
   int totalMoves = 0;
   if (numDisk > 0)
   {
       totalMoves = hanoi(startPeg, endPeg, swapPeg, numDisk-1);
       moveDisk(startPeg, endPeg);
       totalMoves += hanoi(startPeg, endPeg, swapPeg, numDisk-1); // count total moves
   }
   return totalMoves;  
}

void moveDisk(pegType &startPeg, pegType &endPeg)
{
   assert(startPeg.diskStack.size() > 0); // makes sure that there is something on the peg

   if (endPeg.diskStack.size() > 0)
   {
       assert(startPeg.diskStack.back() < endPeg.diskStack.back()); // make sure that the start peg has less than goal peg
   }

   startPeg.diskStack.pop_back();
   int n = startPeg.diskStack.back();
   cout << "\nMove Disk " << n << " from peg" << startPeg.name << " to peg" << endPeg.name;
   endPeg.diskStack.push_back(n);
}

PLEASE HELP ME FIGURE OUT WHY MY ASSERT DOESNT WORK! //  assert(startPeg.diskStack.back() < endPeg.diskStack.back()); THIS LINE IS WHEN IT ENDS

Answer 1

#include <iostream>
#include <vector>
#include <cassert>

using namespace std;

// function prototypes
int loadDisk(vector<int> &firstPeg, int numDisks);
void printPeg(vector<int> &peg);
int hanoi(struct pegType &startPeg, struct pegType &swapPeg, struct pegType &endPeg, int numDisk);
void moveDisk(struct pegType &startPeg, struct pegType &endPeg);

struct pegType
{
   vector <int> diskStack;
   int name;
};

int main()
{
   int numDisk = 7;
   int i;

   pegType peg1, peg2, peg3;

   peg1.name = 1;
   peg2.name = 2;
   peg3.name = 3;

   cout << "-------------------------------" << endl;
   cout << " Towers of Hanoi " << endl;
   cout << "-------------------------------" << endl << endl;

   loadDisk(peg1.diskStack, numDisk); // Load Peg 1 with 7 disks

   cout << "
peg1 has " << peg1.diskStack.size() << " discs";
   cout << "
peg2 has 0" << " discs";
   cout << "
peg3 has 0" << " discs" << endl;

   cout << "Starting Condition: " << endl << endl;
   printPeg(peg1.diskStack);
   printPeg(peg2.diskStack);
   printPeg(peg3.diskStack);

   int total = hanoi(peg1, peg3, peg2, numDisk);

   cout << "End Condition: " << endl << endl;
   printPeg(peg1.diskStack);
   printPeg(peg2.diskStack);
   printPeg(peg3.diskStack);

   cout << "A stack of " << numDisk << " can be transferred in " << total << " moves!" << endl;

   system("pause");
   return 0;
}


// function definitions

int loadDisk(vector<int> &pegType, int numDisks)
{
   int i;

   for (i = numDisks; i > 0; i--)
   {
       pegType.push_back(i);
   }

   return i;
}

void printPeg(vector<int> &peg)
{
   for (unsigned int i = 0; i < peg.size(); i++)
   {
       cout << peg[i] << endl;
   }
}

int hanoi(pegType &startPeg, pegType &swapPeg, pegType &endPeg, int numDisk)
{
   int totalMoves = 0;
   if (numDisk > 0)
   {
        if(numDisk != 1)
                totalMoves = hanoi(startPeg, endPeg, swapPeg, numDisk-1);

        moveDisk(startPeg, endPeg);
        totalMoves += 1;

        if(numDisk != 1)
                totalMoves += hanoi(swapPeg, startPeg, endPeg, numDisk-1); // count total moves
   }
   return totalMoves;  
}


void moveDisk(pegType &startPeg, pegType &endPeg)
{
   assert(startPeg.diskStack.size() > 0); // makes sure that there is something on the peg

   if (endPeg.diskStack.size() > 0)
   {
       assert(startPeg.diskStack.back() < endPeg.diskStack.back()); // make sure that the start peg has less than goal peg
   }

   int n = startPeg.diskStack.back();
   startPeg.diskStack.pop_back();

   cout << "
Move Disk " << n << " from peg" << startPeg.name << " to peg" << endPeg.name;
   endPeg.diskStack.push_back(n);
}

=============

You were first popping, and then taking the backvalue.. which is wrong.. first take back value and then pop.. i have corrected the code above.. Please upvote..