Random food generator

[BadAssPanda]

I want to make random food generator but I dont have an idea how to do it so can anyone explain me or give me example for random food generator on 2d array(map).
Here is my code

#include <iostream>
#include <conio.h>
#include <windows.h>
using namespace std;

    int i, j;
	int posX = 3, posY = 1;
	char player = 'G';
	char trap = 'T';
	char enemy = 'M';
	char treasure = 'X';
	char map[13][13];
	enum eDirecton { STOP = 0, LEFT, RIGHT, UP, DOWN};
    eDirecton dir;
    bool gameOver = false;
    int score = 0;
    char foodX;
    char foodY;

void Setup()
{
    foodX = rand() % i;
    foodY = rand() % j;
}

void Draw()
{
    system("cls");
    for(i=0; i<13; i++)
		{
        for(j=0; j<13; j++)

        cout << map[i][j]<< " ";
        cout << endl;
		}
		cout << "Your score is: " << score << endl;
}

void Input()
{
    if (_kbhit())
	{
		switch (_getch())
		{
		case 'a':
			dir = LEFT;
			break;
		case 'd':
			dir = RIGHT;
			break;
		case 'w':
			dir = UP;
			break;
		case 's':
			dir = DOWN;
			break;
		case 'x':
			gameOver = true;
			break;
		}
	}
}

void Logic()
{
    switch (dir)
	{
	case LEFT:
		if (posX <= 0)
			{
				break;
			}
			else
			{
			map[posY][posX] = '.';
			posX -=1;
			map[posY][posX]= player;
			}
			break;
	case RIGHT:
		if (posX >= 12)
			{

			}
			else
			{
			map[posY][posX] = '.';
			posX +=1;
			map[posY][posX]= player;
			}
			break;
	case UP:
		if (posY <= 0)
			{
                break;
			}
			else
			{
			map[posY][posX] = '.';
			posY -=1;
			map[posY][posX]= player;
			}
			break;
	case DOWN:
		if(posY >= 12)
			{
				break;
			}
			else
			{
			map[posY][posX] = '.';
			posY +=1;
			map[posY][posX]= player;
			}
			     break;
	default:
		break;
	}

}

int main()
{


	for(i=0; i<13; i++){
		for(j=0; j<13; j++){

			map[i][j] = '.';
		}
	}

	map[posY][posX] = player;
	map[2][6] = trap;
	map[4][4] = trap;
	map[5][6] = trap;
	map[6][9] = treasure;

while(true)
{
Draw();
Input();
Logic();
_sleep(100);
}

return 0;
}