my project has stop working

[rabieabouras]

Hi every one .... I am a new student at IT technology......
I cant find the problem here :

#include<iostream>
#include<cmath>

using namespace std;

struct record
{
	float val;
	int power;
};

struct poly
{
	 record num;
	 poly *next;
};




void insert(poly *& , record );
void insertadd(poly *& , record );
void readpoly(poly *&);
void writepoly(poly *);
void addpoly(poly *& , poly *& , poly *&);
void multpoly(poly *& , poly *& , poly *&);

//=====================================================

void main()
{
	
	char choise;
	poly *ph=NULL,*ph1=NULL,*ph2=NULL,*ph3=NULL;


	do 
	{
		cout<<"enter your choise    :"<<endl;
		cout<<"----------------------"<<endl;
		cout<<"press r to read poly :"<<endl;
		cout<<"press w to write poly:"<<endl;
		cout<<"press a to addpoly   :"<<endl;
		cout<<"press m to multpoly  :"<<endl;
		cout<<"press e to end       :"<<endl;
		cout<<"----------------------"<<endl;
		cin>>choise;
		switch (choise)
		{
	     	case ('r'):
			case ('R'):
							 

				readpoly(ph);
								 break;
							 
	    	case ('w'): 
			case ('W'):      {
								 writepoly(ph);
								 cout<<endl;
								 cout<<"-------------------"<<endl;
								 break;
							 }
		    case ('a'):
			case ('A'):
			                 {
								 cout<<"read poly 1 : "<<endl;
								 readpoly(ph1);
								 cout<<"read poly 2 : "<<endl;
								 readpoly(ph2);
								 addpoly(ph1,ph2,ph3);
								 cout<<" ***** add ruselt ******** "<<endl<<endl;
								 writepoly(ph3);
								 cout<<"-----------------------"<<endl;
								 break;
							 }
	    	case ('m'):
			case ('M'):
			                 {
								 cout<<"read poly 1 : "<<endl;
								 readpoly(ph1);
								 cout<<"read poly 2 : "<<endl;
								 readpoly(ph2);
								 multpoly(ph1,ph2,ph3);
								 cout<<" ***** mult ruselt ******** "<<endl<<endl;
								 writepoly(ph3);
								 cout<<"-----------------------"<<endl;
								 break;
							 }
	    	default : 
			                 {
								 cout<<" try again "<<endl;
								 break;
							 }
		}
	}
     while (choise = 'e');
}

//================================================
void insert (poly *&ph,record num3)
{
	poly *temp=new poly,*s,*prv;
	bool located=false;

	temp->num.val=num3.val;
	temp->num.power=num3.power;
	temp->next=NULL;

	if (ph=NULL)
		ph=temp;
	else
	{
		s=ph;
		while ((! located) && (s!=NULL))
		{
			if (s->num.power>num3.power)
			{
				prv=s;
				s=s->next;
			}
			else
				located=true;
		}

		if (s->num.power = num3.power)
		{
			while (s->num.power = num3.power)
			{
				cout<<"error,plz enter new element : ";
				cout<<"enter val :"<<endl;
				cin>>num3.val;
				cout<<"enter power :"<<endl;
				cin>>num3.power;
				insert(ph,num3);
			}
		}
		else
		{
		  temp->next=s;
	      if (s=ph)
			ph=temp;
		  else
			prv->next=temp;
		}
	}
}

//===================================================

void insertadd(poly *&ph,record num)
{
	poly *temp,*s,*prv;
	bool located=false;

	temp= new poly;
	temp->num.power=num.power;
	temp->next=NULL;

	if (ph=NULL)
		ph=temp;
	else
	{
		s=ph;
		while ((! located) && (s!=NULL))
		{
			if (s->num.power>num.power)
			{
				prv=s;
				s=s->next;
			}
			else
				located=true;
		}

		if (s->num.power = num.power)
			s->num.val = s->num.val + num.val;
		else
		{
		  temp->next=s;
	      if (s=ph)
			ph=temp;
		  else
			prv->next=temp;
		}
	}

}

//==================================================

void readpoly(poly *&ph)
{
	int size ;
	record num ;

   cout<<"how many elements do you enter: ";
   cin>> size;
   for (int i=1; i<=size; i++) 
   {
       cout<<"enter value: "<<endl;
       cin>> num.val;
       cout<<"enter power:  "<<endl;
       cin>> num.power;
	   insert (ph,num);
   }

}
//==================================================
void writepoly(poly *ph)
{
	poly *s;
	s=ph;
        while(s != NULL)
		{
			if(s->num.power=0)
				if(s->num.val>0)
					cout<<"+"<<s->num.val;
				else
                    cout<<s->num.val;
			else
				if (s->num.power=1)
					if (s->num.val>0)
						cout<<"+"<<s->num.val<<"x";
					else 
						cout<<s->num.val<<"x";
				else
					if (s->num.val>0)
						cout<<"+"<<s->num.val<<"x^"<<s->num.power;
					else
						cout<<s->num.val<<"x^"<<s->num.power;

			s=s->next;
		}
}
   
//===================================================
void addpoly(poly *&ph1 , poly *&ph2 , poly *&ph3)
{
	poly *t1,*t2; record num1;
	ph3=NULL;
	t1=ph1;
	while (t1 != NULL)
	{
		num1.power=t1->num.power;
		num1.val=t1->num.val;
		insert (ph3,num1);
		t1=t1->next;
	}
	t2=ph2;
	while (t2 != NULL)
	{
		num1.power = t2->num.power;
		num1.val = t2->num.val;
		insertadd(ph3,num1);
		t2=t2->next;
	}	
}
//=================================================

void multpoly (poly *&ph1, poly *&ph2,poly *&ph3)
{
	poly *t1,*t2; 
	record num1,num2,num3;
	ph3=NULL;
	t1=ph1;
	while (t1 != NULL)
	{
		num1.power=t1->num.power;
		num1.val=t2->num.val;
		t2=ph2;
		while (t2 != NULL)
		{
			num2.power=t2->num.power;
			num2.val=t2->num.val;
			num3.val=num1.val * num2.val;
			num3.power=num1.power + num2.power;
			insertadd(ph3,num3);
			t2=t2->next;
		}
		t1=t1->next;
	}
}
//=================================================================================================================== 

[ne555]

main must return int.

= assignment operator
== comparison operator

Your memory is leaking (there isn't a single delete). ¿Are you sure that you need dynamic allocation?

Try to abstract a little more. There is std::list

You can return values from functions