Assistance with c++ map<> type

Question

I'm trying to make a snake clone that runs through the command prompt (baby steps) and I'm not too familiar with c++. Right now the issue I'm having is that when the snake "eats" the fruit the game loop stops. Without the addition of elongating the snake, it works. What I'm trying to do is have the snake body be a map that has an int key, with a tuple (x, y) coordinate. I think the issue is in the Move() function:

tempHead = make_tuple(x, y);
for (int i = 0; i < snakeBody.size(); i++) {

    tempBody = snakeBody.find(i+1)->second;
    snakeBody.find(i+1)->second = tempHead;
    tempHead = tempBody;
}

I'm probably trying to read and put values into the map wrong, which is what I think is the issue but I don't know how I'm supposed to do it. Any help is greatly appreciated. I'm also open to feedback on ways to be doing this better, but I couldn't think of one. Full code (in case I misidentified the issue):

#include <iostream>
#include <chrono>
#include <thread>
#include <string>
#include <Windows.h>
#include <map>

using namespace std;

//time waited before redrawing the screen in miliseconds
chrono::milliseconds timespan(100);

bool gameOver;
//size of the game
const int width = 20;
const int height = 20;
//number of squares
const int area = width * height;

int x, y, fruitX, fruitY, score;

//tuples for storing (x,y) coords for moving the snake along
tuple<int, int> tempHead;
tuple<int, int> tempBody;

enum class eDirection { STOP = 0, LEFT = 1, RIGHT = 2, UP = 3, DOWN = 4};
eDirection dir;

//a map containing key, value pairs of (segment, tuple<x, y>)
map<int, tuple<int, int>> snakeBody;

void Setup() {

    //you're not losing the game yet
    gameOver = false;
    //snake isn't moving
    dir = eDirection::STOP;

    //centered snake
    x = width / 2;
    y = height / 2;
    snakeBody.insert(make_pair(1, make_tuple(x, y)));
    
    //random gen fruit
    fruitX = rand() % width;
    fruitY = rand() % height;

    //clear score
    score = 0;

}
void Draw() {

    //clear the screen
    system("cls");

    //top row
    for (int i = 0; i < width; i++) {

        cout << "#";

    }
    cout << endl;

    //draw the board
    for (int i = 0; i < height; i++) {
        for (int j = 0; j < width; j++) {

            //fruit
            if (j == fruitX && i == fruitY) {
                cout << ".";
            }
            //walls
            else if (j == 0 || j == width - 1) {
                cout << "#";
            }
            //snake
            else if (j == x && i == y) {
                cout << "0";
            }
            //empty
            else {
                cout << " ";
            }
        }
        cout << endl;
    }
    //bottom row
    for (int i = 0; i < width; i++) {

        cout << "#";

    }
    cout << endl;
    cout << score;
}
//movement keys are wasd
void Input() {

    if (GetAsyncKeyState('W') & 0x8000) {
        dir = eDirection::UP;
    }
    if (GetAsyncKeyState('A') & 0x8000) {
        dir = eDirection::LEFT;
    }
    if (GetAsyncKeyState('S') & 0x8000) {
        dir = eDirection::DOWN;
    }
    if (GetAsyncKeyState('D') & 0x8000) {
        dir = eDirection::RIGHT;
    }
}
int Move(eDirection dir) {

    //where to move the head to
    if (dir == eDirection::UP) {
        y -= 1;
    }
    if (dir == eDirection::DOWN) {
        y += 1;
    }
    if (dir == eDirection::LEFT) {
        x -= 1;
    }
    if (dir == eDirection::RIGHT) {
        x += 1;
    }
    if (dir == eDirection::STOP) {
        x = x;
        y = y;
    }
    //replace each value in snakeBody with the one ahead of it
    tempHead = make_tuple(x, y);
    for (int i = 0; i < snakeBody.size(); i++) {

        tempBody = snakeBody.find(i+1)->second;
        snakeBody.find(i+1)->second = tempHead;
        tempHead = tempBody;
    }
    return 0;
}
//adds the given x,y to the map with an auto-incremented key
int increaseSnake(map<int, tuple<int, int>> map, int x, int y) {
    
    int mapSize = map.size();

    while (map.size() < area){
    
        map.insert(make_pair(mapSize + 1, make_tuple(x, y)));
    }
    return 0;
}
void Logic() {
    
    Move(dir);
    
    //if the snake "eats" fruit
    if (x == fruitX && y == fruitY) {
        score += 1;
        fruitX = rand() % width;
        fruitY = rand() % height;
        increaseSnake(snakeBody, x, y);
    }
    //if the snake touches a wall
    if (x == width - 1 || x == 0 || y == height - 1 || y == -2) {
        gameOver = true;
    }
}

int main() {

    Setup();
    //gameloop
    while (!gameOver) {

        Draw();
        Input();
        Logic();
        //reduce flickering
        this_thread::sleep_for(timespan);
    }
    //gameover screen
    cout << endl;
    cout << "Game over! You scored: " << score << endl;
    cout << "pause";
    return 0;

}

Answer 1

In here

while (map.size() < area){

    map.insert(make_pair(mapSize + 1, make_tuple(x, y)));
}

At start

map.size() == 1
area == width * height == 40

When you get in increaseSnake(), wouldn't that loop add same (x, y) coordinates for 40 times.

You probably wanted an if condition.

If increaseSnake() always gonna return 0, why even have it.

You should use std::vector<std::pair<int, int>> instead.

When finding for a key in map, you should check if the key is really found before using the return value. But better use above suggestion instead.