why doesn't this replace the 'Xs' with space's - c++

Question

int mapSizeX = 30;
int mapSizeY = 10;
string map[10][30];
char playerMovement;
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
map[i][j]= "X";
cout << map[i][j];
}
cout << endl;
}
for (int i = 1; i < mapSizeY - 1; i++)
{
for (int j = 1; j < mapSizeX - 1; j++)
{
map[i][j] = " ";
cout << map[i][j];
}
cout << endl;
}
this for some reason doesn't replace the X's with spaces and adds it after the X's and doesn't make a "arena", this is for a snake game by the way

Answer 1

You're outputting to cout twice. Remove both cout << map[i][j]; from the loops and output only when you are done editing the string:
... // Previous code without printing
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
cout << map[i][j];
}
cout << endl;
}

Answer 2

Try adding the following to see your arena:
cout << endl << endl;
cout << "The arena: " << endl << endl;
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
cout << map[i][j];
}
cout << endl;
}

Answer 3

After you printed the entire arena with X's, you then print the entire arena with white spaces just one tile shorter on each side. So you're printing them after eachother. What you wanna do instead is to print them in the same nested for loop, like this:
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
if (i == 0 || j == 0 || i == mapSizeY - 1 || j == mapSizeX - 1) {
map[i][j] = "X";
cout << map[i][j];
}
else {
map[i][j] = " ";
cout << map[i][j];
}
}
cout << endl;
}
The if-clause checks if the current iteration is an edge (if its 0 on X or Y axis or if its the last element in the array on X or Y axis) and prints the X, if its not (its in the field) it prints a blank space.
Little tip I wanna give you: I would initialize the field straight away with the characters without printing it.
So initialize the field like this:
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
if (i == 0 || j == 0 || i == mapSizeY - 1 || j == mapSizeX - 1) {
map[i][j] = "X";
}
else {
map[i][j] = " ";
}
}
}
and then after you've done the equations on the snake, food and stuff and written that all into you ´map´ vairable, go and print the whole map like this:
for (int i = 0; i < mapSizeY; i++)
{
for (int j = 0; j < mapSizeX; j++)
{
cout << map[i][j];
}
cout << endl;
}
Hope I could help!