C :

#include<stdio.h>
main()
{
	int i,j,n;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		for(j=1;j<=n;j++)
		{
			if(i==1||i==n)
			{
				printf("*");
			}
			else
			{
			    if(j==1||j==n)
			    {
				    printf("*");
			    }
			    else
			        printf(" ");
		    }
		}
		printf("\n");
	}
}

C++ :

#include <bits/stdc++.h>
using namespace std;

int main()
{
	int i,j,n;
	cin>>n;
	for(i = 1;i <= n;i++){
		for(j = 1;j <= n;j++){
			if(i == 1 || i == n){
				cout<<"*";
			}else{
				if(j == 1 || j == n){
					cout<<"*";
				}else{
					cout<<" ";
				}
			}
		}
		
		cout<<endl;
	}
}

Java :

import java.util.*;
    public class Main{
        public static void main(String args[]){
            Scanner sc=new Scanner(System.in);
            int n=sc.nextInt();
            for(int i=1;i<=n;i++){
            	for(int j=1;j<=n;j++){
            		if(i==1||i==n||j==1||j==n){
            			System.out.print("*");
            		}
            		else{
            			System.out.print(" ");
            		}
            	}
            	System.out.println();
            }
    }
}

Python :

n = int(input())
for i in range(1, n + 1):
    for j in range(1, n + 1):
        if i == 1 or i == n:
            print('*', end='')
        else:
            if j == 1 or j == n:
                print('*', end='')
            else:
                print(' ', end='')
    print()