Answer 1

I do not know why you want a for loop for this, it's incredibly inefficient when you could just do

std::cout << "*\n**\n***\n**\n*";

But if you insist...

#include <iostream>
#include <string>

int main()
{
for (int i = 1; i <= 4; i++)
{
if (i == 4)
{
std::cout << "**\n*";
break;
}
std::cout << std::string (i, '*') << "\n";
}
}