C :

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

    for(k=1;k<i;k++)
    printf(" ");
	for(j=2*(n-i+1)-1;j>=1;j--)
	{
		printf("#");
	}
	printf("\n");
		}
		return 0;
	
	
	
	
	
	
	
}

C++ :

#include<iostream>
using namespace std;
int main()
{
  int n;
  cin>>n;
  for (int i=1;i<=n;++i)
  {
    for (int j=1;j<=i-1;++j) 
		cout<<" ";
    for (int k=1;k<=2*(n-i)+1;++k)
    cout<<"#";
  cout<<endl;}
   return 0;
}