kare.c

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