未定义的标识符

Question

我正在学习C++并制作了一个脚本，一个攻击怪物类型的非常基本的玩家。但我得到未定义的标识符问题=/

我不太明白为什么，我来自PHP背景，所以它可能并不完全适应C++严格的方式，但我希望有人能解释。

的错误：

main.cpp(30): error C2065: 'miss' : undeclared identifier 
main.cpp(31): error C2065: 'hit' : undeclared identifier 
main.cpp(43): error C2065: 'pmiss' : undeclared identifier 
main.cpp(46): error C2065: 'phit' : undeclared identifier 
main.cpp(47): error C2065: 'phit' : undeclared identifier 
main.cpp(49): error C2065: 'mmiss' : undeclared identifier 
main.cpp(52): error C2065: 'mhit' : undeclared identifier 
main.cpp(53): error C2065: 'mhit' : undeclared identifier 

我的脚本：

#include <iostream> 


int player_health = 10; 
int monster_health = 10; 

void main(){ 

    do{ 
     std::cout << "#####################################" << std::endl; 
     std::cout<< "Pick you're weapon and hit enter!" << std::endl; 
     std::cout << "Press k for knife or b for Bat!" << std::endl; 
     std::cout <<""<<std::endl; 
     std::cout << "Player Health: "<< player_health << std::endl; 
     std::cout << "Monster Health: "<< monster_health << std::endl; 
     std::cout << "###################################"<< std::endl; 
     std::cout<<""<<std::endl; 

     char user_weapon; 
     std::cin >> user_weapon; 

     if(user_weapon == 'k' || user_weapon == 'b'){ 
      if(user_weapon == 'k'){ 
       int miss = 5; 
       int hit = 5; 
      } else if(user_weapon == 'b'){ 
       int miss = 2; 
       int hit =3; 
      } 
       if((rand() % miss) < 3){ 
        int phit = (rand()% hit); 
       } else { 
        bool pmiss = true; 
       } 

      //monster 
      if((rand() % 5) < 3){ 
      int mhit = (rand()%3); 
      } else { 
       bool mmiss = true; 
      } 

      if(pmiss){ 
       std::cout << "Player missed monster!"<<std::endl; 
      }else{ 
       monster_health = monster_health - phit; 
       std::cout << "Player hit monster for " << phit << "!" << std::endl; 
      } 
      if(mmiss){ 
      std::cout << "Monster missed player!"<<std::endl; 
      } else{ 
       player_health = player_health - mhit; 
      std::cout << "Monster hit for " << mhit << "!" <<std::endl; 
      } 
     } else { 
      std::cout << "Invalid input , try either k or b" << std::endl; 
     } 


    }while(player_health >0 || monster_health > 0); 
     std::cout << "###################################"<< std::endl; 
     std::cout<<""<<std::endl; 
    if(player_health < 0 && monster_health < 0){ 
     std::cout << "It's a draw!" << std::endl; 
    } else if (player_health > monster_health){ 
     std::cout<<"Player Wins!" << std::endl; 
    } else { 
     std::cout<<"Monster Wins!" << std::endl; 
    } 
     std::cout << "###################################"<< std::endl; 
     std::cout<<""<<std::endl; 
} 

如果您运行脚本和我一样，你应该得到同样的错误。

Answer 1

if(user_weapon == 'k'){ 
       int miss = 5; 
       int hit = 5; 
      } else if(user_weapon == 'b'){ 
       int miss = 2; 
       int hit =3; 
      } 
       if((rand() % miss) < 3){ 

您正在定义miss在if的范围，然后在使用它的范围，所以：if((rand() % miss) < 3){，你会得到miss是不确定的 - 因为它仅被定义在你声明的范围它。

请注意，在C++中，你不能这样做，在C++中有静态作用域。

您应该在if作用域之前定义miss，并且仅在此处为其分配值。

当然，这同样适用于其他变量，如hit和pmiss。