C++ ASCII game console screen flickering - c++

Question

I am making a simple game using C++
It's just a tile game with an ASCII map.
The game itself works fine, but the console screen(map) is flickering when I move my player and I don't know how to fix this. Any help appreaciated, thanks!
Code:
#include <iostream>
#include <windows.h>
#include <conio.h>
#include <ctime>
#include <vector>
#include <string>
#include <cstdlib>
#include <fstream>
using namespace std;
vector<string> map;
int playerX = 10;
int playerY = 10;
int oldPlayerX;
int oldPlayerY;
bool done = false;
void loadMap();
void printMap();
void setPosition(int y, int x);
void eventHandling();
int main()
{
loadMap();
map[playerY][playerX] = '#';
printMap();
while(!done){
eventHandling();
printMap();
}
exit(1);
return 0;
}
void eventHandling(){
char command;
command = _getch();
system("cls");
oldPlayerX = playerX;
oldPlayerY = playerY;
if(command == 'w'){
playerY--;
}else if(command == 'a'){
playerX--;
}else if(command == 'd'){
playerX++;
}else if(command == 's'){
playerY++;
}
if(map[playerY][playerX] == '#'){
playerX = oldPlayerX;
playerY = oldPlayerY;
}
setPosition(playerY,playerX);
}
void setPosition(int y, int x){
map[oldPlayerY][oldPlayerX] = '.';
map[y][x] = '#';
}
void printMap(){
for(int i = 0 ; i < map.size() ; i++){
cout << map[i] << endl;
}
}
void loadMap(){
ifstream file;
file.open("level.txt");
string line;
while(getline(file, line)){
map.push_back(line);
}
}

Answer 1

std::cout is not intended to be used that way.
You should refer to the system specific API for the target OS and environment. For example, for Windows you should use Console API functions for your purpose. These functions are defined in Wincon.h include file.

Answer 2

It also helps if you use a double buffering system such that only what needs to be overwritten every frame is changed. IO operations are extremely expensive so ought to be minimized.
Cameron Gives a Very Thorough Description of How to Do this Here
But in essence, you'd use two arrays, one containing the current state of the map, one containing the previous state and only write to the specific locations that have changed.

Answer 3

One method to clear the screen that works on many systems is to print the form feed character, \f. The Linux console supports this, and so did MS-DOS if you loaded ansi.sys. Unix has ncurses and terminfo to abstract these functions.