Why aren't my enemy positions updating?

Question

I'm trying to make a dungeon crawler but I need to make the monster move around each turn.

Here's what I tried:

My map is initialized like this:

char map[10][10];

and this is how I spawn the monsters to avoid overwriting:

void fieldinfo::RandomizeMonsterPositions()
{
    int Mcounter=0;
    amountEnemies=10;
    int i=0;
    srand(time(0));

    do
    {
        MposX=rand()%9;
        MposY=rand()%9;

        if(map[MposX][MposY]==enemy)
        {
            //do nothing
        }
        else if(map[MposX][MposY]==player)
        {
            //do nothing
        }
        else
        {
            map[MposX][MposY] = enemy;
            tempPosX[i]=MposX;
            tempPosY[i]=MposY;
            i++;
            Mcounter++;
        }

    }while(Mcounter<10);
}

You can see that I tried to "save" each monster's position in the tempPosX/Y variables to use them here, in my movement logic:

void fieldinfo::RandomizeMonsterMovement()
{
    int mouvement;
    for(int i; i<amountEnemies; i++)
    {
        mouvement=rand()%0;
        switch(mouvement)
        {
        case 0:
            tempPosX[i]++;
            MposX=tempPosX[i];
            break;
        case 1:
            tempPosX[i]--;
            MposX=tempPosX[i];
            break;
        case 2:
            tempPosY[i]++;
            MposY=tempPosY[i];
            break;
        case 3:
            tempPosY[i]--;
            MposY=tempPosY[i];
            break;
        }
    }
}

This doesn't work and I don't know why?

Answer 1

You're not updating the map when the positions change.

You probably want to do something like the following:

void fieldinfo::RandomizeMonsterMovement()
{
    for(int i = 0; i < amountEnemies; i++)
    {
        // Clears the current position.
        map[tempPosX[i]][tempPosY[i]] = empty;

        // Updates the enemy position.
        const int movement = rand() % 4;
        switch(movement)
        {
        case 0:
            tempPosX[i]++;
            break;
        case 1:
            tempPosX[i]--;
            break;
        case 2:
            tempPosY[i]++;
            break;
        case 3:
            tempPosY[i]--;
            break;
        }

        // Updates the map in the new position.
        map[tempPosX[i]][tempPosY[i]] = enemy;
    }
}

I'm not really sure what you tried to accomplish with MposX and MposY...

Anyways, I've got a basic example program with a single enemy moving around here: https://onlinegdb.com/HknD1eeQG

Please refer to my previous answer on how to improve the general movement system to handle corner cases in a much more improved manner.