Не могу справиться с if!

#include <iostream.h>
#include <stdio.h>
int main()
{
 using namespace std; 
 
 string name;
 cout << "Type name:      ";
 cin >> name;
 
 int life;
 int damage;
 int mana;
 
 int klas;
 cout << "Choose your class: 1 - witcher, 2 - warior, 3 - shooter   ";
 cin >> klas;
 
switch (klas)
{ 
      case 1:
           life = 100;
           damage = 10;
           mana = 150;
           cout << "Your name is " << name << "\n";
           cout << "Your class is witcher  \n";
           cout << "Your life is   " << life << " now. You can upgrade it\n";
           cout << "Your damage is  " << damage << " now\n";
           cout << "And you have " << mana << " mana! It`s really more!\n";
      break;
      case 2:
           life = 160;
           damage = 14;
           mana = 0;
           cout << "Your name is " << name << "\n";
           cout << "Your class is warrior \n";
           cout << "Your life is   " << life << " now. You can upgrade it\n";
           cout << "Your damage is  " << damage << " now\n";
           cout << "And you have no mana, becose you are warrior, yeah. Discrimination.\n";
      break;
      case 3:
           life = 50;
           damage = 20;
           mana = 10;
           cout << "Your name is " << name << "\n";
           cout << "Your class is shooter \n";
           cout << "Your life is   " << life << " now. You can upgrade it \n";
           cout << "Your damage is  " << damage << " now\n";
           cout << "And you have " << mana << " mana! You have mana! It`s cool!\n";
}
int gnomtown;
int elftown;
int orktown;
 
int goo;
cout << "Where you want to go? 1 - to gnomes, 2 - to elftown, 3 - to orktown     ";
cin >> goo;
switch (goo)
{
       case 1:
            cout << "You are in Gnomes Town now! You can repair your armor!"<< endl;
       break;
       case 2:
            cout << "You are in Elfs Town now! You can buy weapon here!"<< endl;
            cout << "Type !shop for shopping!"<< endl;
                int shop;
                cin >> shop;
    if (shop=!shop);
     {
                    cout << "What are you want? Maybe, you want to buy Legendary Sword?" << endl;
                    int buy;
                    cout << "1 - to buy sword, 2 - for bow, 3 - for sniper rifle" << endl;
                    cin >> buy;
                                 switch (buy)
                                 {
                                 case 1:
                                       damage = 17;
                                       cout << "Your damage is 14 + 3 now"<< endl;
                                 break;                                 
                                       
                                 case 2:
                                       damage = 15;
                                       cout << "Your damage is 14 + 1 now"<< endl;
                                 break;
                                 case 3:
                                      if (klas = 2)
                                       {
                                               cout << "You can`t buy this item, becouse you are warrior. Dicramination!"<< endl;
                                               }
                                               else
                                               {
                                                   cout << "Your damage is 20 + 6 now! You are dangerous!"<< endl;
                                               }
                                       }
                    }
 
       break;
       case 3:
            life -= 44;
            cout << "Orks hate you and want to kill you. Run away!\n ";
            cout << "You was damaged. Your health for now  " << life << "\n";
            break;
}
system("pause");
return 0;
}

cin >> shop;
if(shop!=shop)

if(shop==!shop)

if(shop=!shop)

shop=!shop;
if(shop)...

if(shop=!shop)

if(shop==!shop)