Use of arrow keys to generate movement in play

Question

I wanted to know how the developer of the game Snake in C++ merged with C made the snake move from the arrow keys.

I think the part where it moves is when it compares tecla=='K' tecla=='H' and so on, but I wanted to know why he used those letters, and the main.

'Cause when you press the arrow that it doesn’t happen to be these letters the snake moves?

Here comes the code

  #include<windows.h>
  #include<stdio.h>
  #include<conio.h>
  #include<iostream>
  #include <stdlib.h>
  #include <time.h>


  //Código feito com base em tutoriais na internet, desenvolvido por  
  Gustavo    Ferreira do 2 semestre do Curso de Jogos Digitais da FATEC   
  SAO CAETANO DO SUL.

  void mgotoxy(int x, int y)
  {
  SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),(COORD)          
  {x,y});//Percorre a matriz    
  }

  main() 
  {
  int x,d=2,cx[300]={1,2},cy[300]={7,7},t=1,mx,my,velo=100,velo2=5;
  char niv;

  char tecla='a';
  int opcao;
  int pontos=0;
  int nivel = 1;



  for(x=0;x<18;x++)
  { mgotoxy(0,x); //vertical esquerda.//

  printf("%c",219);
  }
  for(x=0;x<50;x++)
  { mgotoxy(x,0); //horizontal superior//
  printf("%c",219);
  }
  for(x=0;x<18;x++)
  { mgotoxy(50,x); //vertical direita//
   printf("%c",219);
  }
  for(x=0;x<51;x++)
  { mgotoxy(x,18); //horizontal inferior.//
  printf("%c",219);
   }

  srand(time(NULL));
  mx=(rand()%49)+1;
  my=(rand()%17)+1;

  velo = 200;

  while(tecla!='s')
  { while(tecla!='s'&&!(tecla=kbhit()))

  { for(x=t;x>0;x--)
  { cx[x]=cx[x-1];
  cy[x]=cy[x-1];
   }

  if(d==0)cx[0]--;
  if(d==1)cy[0]--;
  if(d==2)cx[0]++;
  if(d==3)cy[0]++;
  mgotoxy(cx[t],cy[t]);
  printf(" ");
  if(mx==cx[0]&&my==cy[0])
  { t++;
  pontos++;
  mx=(rand()%25)+1;
  my=(rand()%17)+1;
  velo-=5;
  velo2+=5;

    }
   mgotoxy(cx[0],cy[0]);

   printf("%c",219);

   mgotoxy(mx,my);
   printf("%c",1);
   mgotoxy(55,10);

   printf ("Pontos: %d",pontos);
   mgotoxy(55,5);
   printf ("Nivel: %d",nivel);
   mgotoxy(55,3);
   printf ("Velocidade: %d",velo2);
   mgotoxy(3,22);

   printf ("Jogo desenvolvido por Gustavo Ferreira");
   Sleep(velo);
   for(x=1;x<t;x++)
   { if(cx[0]==cx[x]&&cy[0]==cy[x])tecla='s';
   }
   if(cy[0]==0||cy[0]==18||cx[0]==0||cx[0]==50)tecla='s';

     }
   if(tecla!='s')tecla=getch();
   printf("%c",tecla);
   if(tecla=='K')d=0;
   if(tecla=='H')d=1;
   if(tecla=='M')d=2;
   if(tecla=='P')d=3;
   if(cy[0]==0||cy[0]==18||cx[0]==0||cx[0]==26)tecla='s';

  }
 system("cls");
 system("pause");

 printf ("\n\n\tVOCE PERDEU\n\n");

 printf ("\n\n\tVOCE FEZ %d PONTOS",pontos);







   getch();
    }

Answer 1

This code has nothing C++, is very bad and I would not waste time with it. Learn with good codes. It uses bad techniques, bad style, is confusing, uses what is not available in all compilers, I doubt it does what was thought and has errors, in fact it even compiles.

The permissible keys are K, H, M, P.

In the specific compiler he used, and probably only in it, these keys have the same code as the arrow keys and so the choice must have been made, the intention is not to use them but to use the arrow keys.