C++ Nested Loops: n*n grid - c++

Question

I need help with this assignment.
I already tried something and I can include the code that I wrote so far.
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
int i, j, n;
cout << "Please enter the positive integer:";
cin >> n;
if (n < 0) {
cout << "\nEntered integer is not positive! Please enter the positive integer:";
cin >> n;
}
for (i = 1; i <= n; i++) {
for (j = 1; j <= n; j++) {
if (i == 1 || i == n || j == 1 || j == n) {
cout << setw(n) << "*";
}
else {
cout << setw(n) << " ";
}
}
cout << endl << "\n";
}
return 0;
}
Thanks in advance!

Answer 1

There are several issues in your implementation:
if (n < 0) {
cout << "\nEntered integer is not positive! Please enter the positive integer:";
cin >> n;
}
The above condition will validate the user input only once. If the user enter a negative number more than once, it will not be checked.
cout << endl << "\n";
This will cause two end of lines to be printed, which is not needed.
Here is a working program which does the required job:
int main()
{
int n;
cout << "Please enter the positive integer: ";
cin >> n;
while (n < 0) {
cout << "\nEntered integer is not positive! Please enter the positive integer: ";
cin >> n;
}
for (int i = 0; i <= (n*n); i++) {
for (int j = 0; j <= (n*n); j++) {
if (i == 0 || (i % n == 0) || (j == 0) || (j % n == 0)) {
cout << setw(2) << "*";
} else {
cout << setw(2) << " ";
}
}
cout << '\n';
}
return 0;
}
Here is the output from the program:

Answer 2

Assuming a 1x1 grid looks like this:
****
* *
* *
****
e.g., is not also dependent on the number inputted, I would use the following:
for (int i = 0; i < n * 3 + 1; ++i) {
cout << "*"; //First row with stars
}
cout << endl;
for (int i = 0; i < n; ++i) {
cout << "*"; //First column with stars
for (int j = 0; j < n; ++j) {
cout << " *"; //Empty box and closing star
}
cout << endl;
cout << "*"; //First column with stars
for (int j = 0; j < n; ++j) {
cout << " *"; //Empty box and closing star
}
cout << endl;
for (int j = 0; j < n * 3 + 1; ++j) {
cout << "*"; //Bottom row of box with stars
}
cout << endl;
}
This code is not tested but just quickly typed, it might not work, so be careful using it. Let me know if there are some problems.