How can i make the border appear one by one?

[csnotsure]

My border appear automatic complete but my professor want that it should appear one by one? How can I do that? Here is my code:

#include <iostream>

int main(void)
{
int r, c;

for( r = 0; r < 50; ++r )
{
for( c = 0; c < 50; ++c )
{
if( r == 0 || r == 49 )
{
std::cout << "*";
}
else
{
if( c == 0 || c == 49 )
std::cout << "*";
else
std::cout << " ";
}
}
std::cout << "\n";
}

return 0;
}

[Peter87]

What do you mean? Should the border not be outputted all at once?

[YFGHNG]

I'm thinking what @OP wants is maybe take an empty character input, like enter or space, and have the border appear one at a time?