C :

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

C++ :

#include <iostream>
using namespace std;
int main(){
	int i,n,j;
	cin>>n;
	//i循环控制输出n行 
	for(i = 1;i <= n;i++){
		//j循环控制每行输出n个数 
		for(j = 1;j <= n;j++){
			cout<<j;
		}
		cout<<endl; 
	}
}

Python :

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