C :

int main(){
         int n,i,j,z;
         scanf("%d",&n);
                  for(i = 1;i <= n+1;i++){
                   for(j=1;j <= n-i+1;j++){
                            printf(" ");
                   }
                  
                   for(z = 1;z <= 2 * i-1;z++){
                            printf("*");
                   }
                   printf("\n");
         
         } 
         
                   
                  for(i = n;i >= 1;i--){
                   
                   for(j = 0;j < n-i+1;j++){
                            printf(" ");
                   }
                   
                   for(z=1;z <= 2 * i - 1;z++){
                            printf("*");
                   }
                   
                   printf("\n");
         }
 

         
        
         return n;
}

C++ :

#include <iostream>
using namespace std;

int main(){
	int i,j,n;
	cin>>n;
	n = n + 1;
	for(i = 1;i <= n - 1;i++){
		for(j = 1;j <= n - i;j++){
			cout<<" ";
		}
		
		for(j = 1;j <= 2 * i - 1;j++){
			cout<<"*";
		} 
		cout<<endl;
	}
	
	for(i = n;i >= 1;i--){
		for(j = 1;j <= n - i;j++){
			cout<<" ";
		}
		
		for(j = 1;j <= 2 * i - 1;j++){
			cout<<"*";
		} 
		cout<<endl;
	}
	return 0;
}

Pascal :

program p1;
var n,i,j,k:integer;
    a:array[1..100] of integer;
begin
  readln(n);
  for i:=1 to (2*n+1) do
    begin
      if (i mod 2)=1 then a[i]:=((i-1) div 2)
      else a[i]:=((i div 2)-1);
    end;
  for i:=1 to (n+1) do
    begin
      for j:=1 to abs(n+1-i) do
        write(' ');
      for k:=1 to (2*i-1) do
        write('*');
        writeln;
    end;
  for i:=(n+2) to (2*n+1) do
    begin
      for j:=1 to abs(n+1-i) do
        write(' ');
      for k:=1 to (4*n+3-2*i) do
        write('*');
        writeln;
    end;
end.

Java :

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
	@SuppressWarnings({ "resource" })
	Scanner scanner=new Scanner(System.in);
	int n=scanner.nextInt();
	for (int a=1;a<=n+1;a++) {
		for (int b=n;b>=a;b--) 
			System.out.print(" ");
		for (int b=1;b<=a;b++)
			System.out.print("*");
		for (int b=1;b<a;b++)
			System.out.print("*");
		System.out.println(" ");}
	
	for (int a=1; a<=n+1; a++){ 
        for (int b=1; b<=a; b++)
		System.out.print (" ");
		    for (int c=n; c>=a;c--)
			System.out.print ("*");
			for (int c=n; c>a;c--)
			System.out.print ("*");
   System.out.println ();
		}
	}	
}

Python :

n = int(input());
n = n+1
for a in range (1, n + 1):
    for b in range (1, n - a +1):
        print('',end=' ')
    for c in range (1, 2*a):
        print('*',end='')
    print()
for i in range(2, n + 2):
    for k in range(2, i+1):
        print(end=' ')
    for x in range(i ,2*n-i+1 ):
        print('*', end = '')
    print()