Stock maintain in c + +

#include<iostream.h>
#include<conio.h>
class item
{
private:
long double availablebook,salebook,orderbook,totalorderbook,availablesupplierbook,totalsupplierbook,ordervendorbook,vendorbooktotal;

int availablejeans,salejeans,totalorderjeans,supplierjeans,availablesupplierjeans,totalsupplierjeans,ordervendorjeans,vendortotal,costorderjeans;
// float  totalcostorderjeans;
 int totalcostb;
 //long double totalcost;
public:
void itemb();
void itembsupplier();
void vendorb();
void itemj();
void  itemjsupplier();
//void stock();
void vendorj();
//void supplier();
};
void item::itemb()
{
int op;
int book=60;
cout<<"\n\n -->Dear customer how many books do u want:";
cin>>salebook;
int perbookcost=120;
cout<<"\n\n -->Per book cost:"<<perbookcost;
totalcostb=perbookcost*salebook;
cout<<"\n\n -->Total amount to be payable by customer:"<<totalcostb;
cout<<"\n\n       ^^^Thanku for purchasing my dear customer^^^";
cout<<"\n\n           ^^Have a nice day^^";
availablebook=book-salebook;
cout<<"\n\n -->Available stock book have shopper:"<<availablebook;
if(availablebook<10)
{
cout<<"\n\n-->Dear shoper your stock is low:";
cout<<"\n\n-->Dear shopper contact your supplier please press 1:";
cin>>op;
switch(op)
{
case 1:

itembsupplier();
break;
}
}
}
void item::itembsupplier()
{
float totalcostorderbook;
int op;
int supplierbook=600;
cout<<"\n\n-->Dear my  client please enter how many books do u purchase:";
cin>>orderbook;
int costorderbook=100;
cout<<"\n\n-->Per book cost:"<<costorderbook;
totalcostorderbook=costorderbook*orderbook;
cout<<"\n\n-->Amount to be payable of supplier"<<totalcostorderbook;
cout<<"\n\n\n  ^^^Thanku for purchasing my shopper^^^";
cout<<"\n\n           ^^Have a nice day^^";
totalorderbook=orderbook+availablebook;
cout<<"\n\n-->Available new stock books have shopper:"<<totalorderbook;
availablesupplierbook=supplierbook-orderbook;
cout<<"\n\n-->Available stock in supplier"<<availablesupplierbook;
if(availablesupplierbook<100)
{
cout<<"\n\n-->Dear supplier your stock is low:";
cout<<"\n\n-->Dear supplier do u want to contact your vendor press 1:";
cin>>op;
switch(op)
{
case 1:
vendorb();
break;
}
}
}
void item::vendorb()
{
cout<<"\n\n-->Dear supplier how many books wants to purchase:";
cin>>ordervendorbook;
int pbc=90;
cout<<"\n\n-->Per book cost:"<<pbc;
float tvb=ordervendorbook*pbc;
cout<<"\n\n-->Total amount to be payable by supplier:"<<tvb;
cout<<"\n\n\n    ^^^ Thanku for purchasing my supplier ^^^";
cout<<"\n\n          ^^ Have a nice day ^^";
vendorbooktotal=ordervendorbook+availablesupplierbook;
cout<<"\n\n-->Available new stock have supplier:"<<vendorbooktotal;
 }
void  item::itemj()
{
double totalcostj=0,jeans=600;
int op;

float perjeanscost;
cout<<"\n\n -->Dear customer how many jeans do u want to buy:";
cin>>salejeans;
perjeanscost=600;
totalcostj=salejeans*perjeanscost;
cout<<"\n\n -->Total amount to be payable by customer:"<<totalcostj;
cout<<"\n\n              ^^^Thanku for purchasing^^^";
cout<<"\n\n                   ^^Have a nice day^^";
availablejeans=jeans-salejeans;
cout<<"\n\n -->Availble stock jeans have shopper           :"<<availablejeans;
if(availablejeans<100)
{
cout<<"\n\n -->Dear shopper your stock is low:";
cout<<"\n\n -->Dear shoper dou want to contact your supplier please press 1:";
cin>>op;
switch(op)
{
case 1:
itemjsupplier();
break;
}
}
}
void item::itemjsupplier()
{
long double totalcostorderjeans;
float orderjeans;
int op;
supplierjeans=6000;
cout<<"\n\n  ->Dear my client please enter how many jeans do u purchase:";
cin>>orderjeans;
costorderjeans=500;
cout<<"\n\n-->Cost of per jeans                       :"<<costorderjeans;
totalcostorderjeans=costorderjeans*orderjeans;
cout<<"\n\n-->Totalamount to be payable by shopper    :"<<totalcostorderjeans;
cout<<"\n\n\n   ^^^Thanku for purchasing my shopper^^^";
cout<<"\n\n        ^^Have a nice day^^";
totalorderjeans=orderjeans+availablejeans;
cout<<"\n\n-->Available new  stock  jeans have shopper:"<<totalorderjeans;
availablesupplierjeans=supplierjeans-orderjeans;
cout<<"\n\n-->Available supplier stock                :"<<availablesupplierjeans;
if(availablesupplierjeans<1000)
{
cout<<"\n\n-->Dear supplier your stock is low :";
cout<<"\n\n-->Dear supplier do u want to contact to vendor press 1:";
cin>>op;
switch(op)
{
case 1:
 vendorj();
 break;
}
}
}
void item::vendorj()
{
cout<<"\n\-->Dear supplier how many jeans do u want to purchase:";
cin>>ordervendorjeans;
float pjc=400;
cout<<"\n\n-->Per jeans cost                        -->   :"<<pjc;
double tvc=ordervendorjeans*pjc;
cout<<"\n\n-->Total amount to be payable by supplier      :"<<tvc;
cout<<"\n\n\n     ^^^Thanku for purchasing my supplier^^^";
cout<<"\n\n               ^^Have a nice day^^";
vendortotal=availablesupplierjeans+ordervendorjeans;
cout<<"\n\n-->Available new stock of supplier jeans have  :"<<vendortotal;
}
// here main function start////
int main()
{
item i;
int op,op1,op2,opa,opa1;
clrscr();
cout<<"\n\n ->Enter 1 for book:";
cout<<"\n\n ->Enter 2 for jeans:";
cout<<"\n\n ->Enter 3 for shirt:";
cout<<"\n\n ->Dear customer please select your choice";
cin>>op;
switch(op)
{
case 1:

cout<<"\n \n\n -->This item is availaible";
cout<<"\n \n -->Dear customer this product want to buy press 1:";
cout<<"\n \n -->Dear customer do u want to go to main menu press 2:";
cout<<"\n \n -->Dear customer please select your choice:";
cin>>op1;
switch(op1)
{
case 1:

     item i;
     i.itemb();
     cout<<"\n\n -->Enter 1 for  main menu";
     cin>>op2;
     switch(op2)
     {
     case 1:
     main();

break;
}
break;
case 2:
main();
break;
}
case 2:
cout<<"\n\n  -->Dear customer this item is available";
cout<<"\n\n  -->Dear customer do u want to buy please press 1:";
cout<<"\n\n  -->Dear customer du want to go to main menu please press 2:";
cout<<"\n\n  -->Dear customer please enter your choice:";
cin>>opa;
switch(opa)
{
case 1:
item i;
i.itemj();
cout<<"\n\n -->Enter 1 for main menu:";
cin>>opa1;
switch(opa1)
{
case 1:
main();
break;
}
break;
case 2:
main();
break;
}
break;
}
getch();
return 0;
}