C :

#include<stdio.h>
void main()
{
	int n;
	scanf("%d",&n);
	int a,b;
	for(a=1;a<=n/2+1;a++){
		
		for(b=1;b<=a;b++){
			printf("*");
		}
	
		for(b=1;b<=2*(n/2-a)+2;b++){
			printf(" ");
		}
		for(b=1;b<=a;b++){
			printf("*");
		}
		printf("\n");
	}
	for(a=1;a<=n/2;a++){
		for(b=1;b<=n/2-a+1;b++){
			printf("*");
		}
		for(b=1;b<=2*a;b++){
			printf(" ");
		}
		for(b=1;b<=n/2-a+1;b++){
			printf("*");
		}
		printf("\n");
	}
	
}

C++ :

#include <bits/stdc++.h>
 
using namespace std;
 
int main(){
    int n,i,j;
    cin>>n;
    n=n/2+1;
    for(i=1;i<=n;i++){
    	for(j=1;j<=i;j++){
    		cout<<"*";
		}
		for(j=1;j<=(n-1)*2+1-2*i+1;j++){
			cout<<" ";
		}
		for(j=1;j<=i;j++){
			cout<<"*";
		}
		cout<<endl;
	}
	for(i=n-1;i>=1;i--){
    	for(j=1;j<=i;j++){
    		cout<<"*";
		}
		for(j=1;j<=(n-1)*2+1-2*i+1;j++){
			cout<<" ";
		}
		for(j=1;j<=i;j++){
			cout<<"*";
		}
		cout<<endl;
	}
} 

Java :

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		for(int i = 1 ; i <= n- n/2;i++) {
			for(int j = i  ; j > 0;j--) {
				System.out.print("*");
			}
			for(int j = n + 1 - 2 * i ; j > 0;j--) {
				System.out.print(" ");
			}
			for(int j = i  ; j > 0;j--) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		for(int i = 1 ; i <= n- n/2;i++) {
			for(int j = n- n/2-i; j > 0 ;j--) {
				System.out.print("*");
			}
			for(int j =  2 * i  ; j > 0;j--) {
				System.out.print(" ");
			}
			for(int j = n- n/2-i; j > 0 ;j--) {
				System.out.print("*");
			}
			System.out.println();
		}
		
	}
}	

Python :

n=int(input())
n1=n//2
for i in range(-n1,n1+1):
    if(i!=0):
        print("*"*(n1-abs(i)+1),end="")
        for j in range(1,abs(i)*2+1):
            print(" ",end="")
        print("*"*(n1-abs(i)+1),end="")    
        print()
    else:
        print("*"*(n1+1)*2)