C :

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

C++ :

#include <iostream>
using namespace std;

int main(){
	int i,j,n;
	cin>>n;
	for(i = 1;i <= n;i++){
		for(j = 1;j <= n;j++){
			cout<<"*";
		} 
		cout<<endl;
	}
	return 0;
}

Python :

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