Reputation: 1
Thank you for reading this thread. I am a beginning programmer and am trying to make a simple snake game with C++. It isn't finished yet, but I think I got a nice start to it. However, when I try to run the program it instantly crashes. (The compiler says there are 0 warnings and errors. I am using the Code::Blocks IDE. Does anyone know why my program isn't working? I think it may have something to do with the "vector coordHistory", but I can't tell for sure. At least that is the last thing I added to the program.
This is my code:
#include <iostream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <windows.h>
#include <conio.h>
#include <vector>
#define MAXX 156 //Number of columns that fits on my screen
#define MAXY 62 //Number of rows that fits on my screen
using namespace std;
// This function clears the console window
void clearConsole()
{
system("cls"); //empties console window
};
// This function returns the x position of the cursor
int getcursorX()
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
if(GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
return csbi.dwCursorPosition.X;
}
};
// This function returns the y position of the cursor
int getcursorY()
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
if(GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
return csbi.dwCursorPosition.Y;
}
};
// This function sets the x position of the cursor
void setcursorX(int x)
{
COORD coord = {x, getcursorY()};
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
// This function sets the y position of the cursor
void setcursorY(int y)
{
COORD coord = {getcursorX(), y};
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
// The snake class contains the coordinates of the snake and direction in which it is moving
class Snake
{
private:
bool isAlive;
int snakexCoord;
int snakeyCoord;
char snakeDirection;
int snakeLength;
public:
//getters
int getsnakexCoord() { return snakexCoord; };
int getsnakeyCoord() { return snakeyCoord; };
char getsnakeDirection() { return snakeDirection; };
bool getisAlive() { return isAlive; };
int getsnakeLength() { return snakeLength; };
//setters
void setsnakexCoord(int newsnakexCoord) { snakexCoord = newsnakexCoord;};
void setsnakeyCoord(int newsnakeyCoord) { snakeyCoord = newsnakeyCoord;};
void setsnakeDirection(char newsnakeDirection) { snakeDirection = newsnakeDirection;};
void setisAlive(bool newisAlive) { isAlive = newisAlive; };
void setsnakeLength(int newsnakeLength) { snakeLength = newsnakeLength; };
//constructor
Snake()
{
snakexCoord = MAXX / 2;
snakeyCoord = MAXY / 2;
snakeDirection = 'E';
isAlive = true;
snakeLength = 1;
};
//destructor
~Snake(){};
};
int main()
{
int i; //iterator
system("mode 650"); //makes console window full-screen
Snake snake; //initializes Snake object snake
char c; //char that stores user input to change snake direction
vector<int[2]> coordHistory; //vector of arrays that stores previous locations of snake
while (snake.getisAlive())
{
//Adds snake coordinates to coordHistory
coordHistory[coordHistory.size()][0] = snake.getsnakexCoord();
coordHistory[coordHistory.size()-1][1] = snake.getsnakeyCoord();
//Iterates backwards through coordHistory and draws an "O" until the snake is as long as it should be
for(i = coordHistory.size() - 1; i > coordHistory.size() - 1 - snake.getsnakeLength(); i--)
{
setcursorX(coordHistory[i][0]);
setcursorY(coordHistory[i][1]);
cout << "O";
}
//Allows user to change snake direction
c = _getch();
switch (c){
case 'w':
snake.setsnakeDirection('N');
break;
case 'd':
snake.setsnakeDirection('E');
break;
case 's':
snake.setsnakeDirection('S');
break;
case 'a':
snake.setsnakeDirection('W');
break;
}
//Checks in which direction snake is going and changes coordinates accordingly
switch (snake.getsnakeDirection())
{
case 'N':
snake.setsnakeyCoord(snake.getsnakeyCoord()-1);
break;
case 'E':
snake.setsnakexCoord(snake.getsnakexCoord()+1);
break;
case 'S':
snake.setsnakeyCoord(snake.getsnakeyCoord()+1);
break;
case 'W':
snake.setsnakexCoord(snake.getsnakexCoord()-1);
break;
}
//Checks if snake goes out of boundaries
if ((snake.getsnakexCoord() > MAXX) || (snake.getsnakexCoord() < 0) || (snake.getsnakeyCoord() > MAXY) || (snake.getsnakeyCoord() < 0))
{
snake.setisAlive(false);
}
//Sleep(200); Ignore WIP
clearConsole();
}
return 0;
}
Upvotes: 0
Views: 111
Reputation: 385405
Your vector usage is wrong.
coordHistory[coordHistory.size()][0] = snake.getsnakexCoord();
coordHistory[coordHistory.size()-1][1] = snake.getsnakeyCoord();
You appear to assume that vector[n-1]
will automatically create as many elements as needed to result in a vector of size n
. It doesn't.
You are twice accessing the first element of vector coordHistory
, a vector which is actually empty.
To add elements, in general use the member function push_back
or emplace_back
. You're really going to struggle with a vector of arrays, though, since arrays are neither assignable nor copyable. That's why I can't use push_back
here; I have to explicitly resize the vector then access the newly-created elements as you were doing before:
coordHistory.resize(1);
coordHistory[0][0] = snake.getsnakexCoord();
coordHistory[0][1] = snake.getsnakeyCoord();
This is pretty awkward. why don't you instead store a nice delicious class type with x
and y
members?
std::vector<deliciousClassType> coordHistory;
coordHistory.emplace_back(
snake.getsnakexCoord(),
snake.getsnakeyCoord()
);
Upvotes: 1