How can I solve assertion failure in c++ 2012?

Question

 The compiler give me this error:

 

 debug assertion failed!!

 

 

This is my code:

 

#include "stdafx.h"
# include <iostream>
# include <string.h>
# include <stdlib.h>
# include <conio.h>
using namespace std;
int top=-1;

char Stack[25][100]={NULL};

void push(const char *);
const char* pop( );

void postfix_to_infix(const char *);

int main( )
{

char Postfix_expression[100]={NULL};

cout<<"\n\n\t Enter the Postfix Expression : ";
cin.getline(Postfix_expression,80);

postfix_to_infix(Postfix_expression);

_getch( );
}


void push(const char *Symbol)
{
if(top==24)
cout<<"Error : Stack is full."<<endl;

else
{
top++;
strcpy_s(Stack[top],Symbol);
}
}

const char* pop( )
{
char Symbol[100]={NULL};

if(top==-1)
cout<<"Error : Stack is empty."<<endl;

else
{
strcpy_s(Symbol,Stack[top]);
_strset_s(Stack[top],NULL);
top--;
}

return Symbol;
}

void postfix_to_infix(const char *Postfix)
{
char Infix_expression[100]={NULL};
char Postfix_expression[100]={NULL};

strcpy_s(Postfix_expression,Postfix);
strcat_s(Postfix_expression,"=");

int count=0;

char Symbol_scanned[5]={NULL};

do
{
Symbol_scanned[0]=Postfix_expression[count];

if(Symbol_scanned[0]=='/' || Symbol_scanned[0]=='*' ||
Symbol_scanned[0]=='-' || Symbol_scanned[0]=='+' ||
Symbol_scanned[0]=='^' )
{
char Value_1[100]={NULL};
char Value_2[100]={NULL};
char Result[100]={NULL};

strcpy_s(Value_1,pop( ));
strcpy_s(Value_2,pop( ));

if(Infix_expression[(count+1)]!='=')
strcpy_s(Result,"(");

strcat_s(Result,Value_2);
strcat_s(Result,Symbol_scanned);
strcat_s(Result,Value_1);

if(Infix_expression[(count+1)]!='=')
strcat_s(Result,")");

push(Result);
}

else
push(Symbol_scanned);

count++;
}
while(Postfix_expression[count]!='=');

_strset_s(Infix_expression,NULL);
strcpy_s(Infix_expression,pop( ));

cout<<"\n\n\t Infix Expression is : "<<Infix_expression;
}