Help with snake

[tennisjad3]

This is what I have so far, I just don't know how to give it the tail. For some reason that is eluding me.

#include <iostream>
#include <ctime>
#include <cstdlib>
#include <Windows.h>

using namespace std;

void clearscreen(); //used to prevent flicker
void movement(int left, int right, int up, int down, int &y, int &x); //used to recoodrinate the snake

int main() {
char map[20][40]; //decleares the map

//loads the bottom and top of the map with a border
for(int i=0; i < 40; ++i) {
map[0][i] = '#';
map[19][i] = '#';
}
//loads the rest of the map with vertical borders and space between them
for(int i=1; i < 19; ++i) {
for(int j=0; j < 41; ++j) {
map[i][0] = '#';
map[i][39] = '#';
if(j < 39) {
map[i][j] = ' ';
}
}
}
char snake = 'o';
int y=9, x=19; //used to coordinate the snake
int left=0, right=0, up=0, down=0; //used to determine which direction the snake should go
int foodcount = 0; //counts ammount of food eaten
int eaten = 0; //used to check if the snake ate food

//generates the food
char food = 'x';
int a, b; //used to position the food
srand(time(0));
a = rand() % 17 + 1;
Sleep(25);
b = rand() % 37 + 1;
map[a][b] = food;

for(;;) { //the game loop
clearscreen();
map[y][x] = snake; //places the snake

//displays the map
for(int i=0; i < 20; ++i) {
for(int j=0; j < 40; ++j) {
cout << map[i][j];
if(j >= 39) {
cout << endl;
}
}
}
cout << "Food eaten: " << foodcount << endl; //displays ammount of food eaten

//checks if the snake moves in another direction
if(GetAsyncKeyState(VK_LEFT)) {
right=0, up=0, down=0;
left = 1;
}
else if(GetAsyncKeyState(VK_RIGHT)) {
left=0, up=0, down=0;
right = 1;
}
else if(GetAsyncKeyState(VK_UP)) {
right=0, left=0, down=0;
up = 1;
}
else if(GetAsyncKeyState(VK_DOWN)) {
left=0, up=0, right=0;
down = 1;
}
//moves the snake
map[y][x] = ' ';
movement(left, right, up, down, y, x);
map[y][x] = snake;

//checks if the player crashed into the border
if(x == 0 || y == 0 || x == 39 || y == 19) {
cout << "\nYou lost!" << endl;
cin.get();
return 0;
}
if(map[y][x] == map[a][b]) {
++foodcount;
++eaten;
}
//if the snake ate food, generate a new one
if(eaten > 0) {
eaten = 0;
a = rand() % 18 + 1;
Sleep(25);
b = rand() % 38 + 1;
map[a][b] = food;
}
}
return 0;
}
void movement(int left, int right, int up, int down, int &y, int &x) {
if(left > 0) {
--x;
return;
}
else if(right > 0) {
++x;
return;
}
else if(up > 0) {
--y;
Sleep(20);
return;
}
else if(down > 0) {
++y;
Sleep(20);
return;
}
}
void clearscreen()
{
HANDLE hOut;
COORD Position;

hOut = GetStdHandle(STD_OUTPUT_HANDLE);

Position.X = 0;
Position.Y = 0;
SetConsoleCursorPosition(hOut, Position);
}