C :

#include <stdio.h>
int main(){
	int n;
	scanf("%d",&n); 
	int i;
	for(i = 1;i <= n / 2 + 1;i++){
		//左空格
		int j;
		for(j = 1;j < i;j++)
			printf(" "); 
		//左*
		printf("X");
		//中空格
		for(j = 1; j <= n - 2 * i;j++)
			printf(" ");
		//右* 
		if(i != n / 2 + 1)
			printf("X");
		//换行 
		printf("\n");
		
	}
	
	//下
	for(i = 1;i <= n / 2;i++){
		//左空格
		int j;
		for(j = 1;j <= n / 2 - i;j++)
			printf(" ");
		//左*
		printf("X");
		
		//中空
		for(j = 1;j <= i * 2 - 1;j++)
			printf(" "); 
		//右*
		printf("X");
		
		//换行 
		printf("\n");
	} 
	return 0;
}

C++ :

#include <iostream>
#include <cmath>
using namespace std;

int main(){
	int n,i,j;
	cin>>n;
	for(i=1;i<=n/2;i++){
		for(j=1;j<=i-1;j++){
			cout<<" ";
		}
		cout<<"X";
		for(j=1;j<=n-i-i;j++){
			cout<<" ";
		}
		cout<<"X"<<endl;
	}
	for(j=1;j<=n/2;j++){
		cout<<" ";
	}
	cout<<"X"<<endl;
	for(i=n/2;i>=1;i--){
		for(j=1;j<=i-1;j++){
			cout<<" ";
		}
		cout<<"X";
		for(j=1;j<=n-i-i;j++){
			cout<<" ";
		}
		cout<<"X"<<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 - 1 ; j > 0;j--) {
				System.out.print(" ");
			}
			System.out.print("X");
			for(int j = n - 2 * i ; j > 0;j--) {
				System.out.print(" ");
			}
			if(i < n - n / 2) {
				System.out.print("X");
			}
			System.out.println();
		}
		for(int i = 1 ; i <= n- n/2-1;i++) {
			for(int j = n- n/2-1-i; j > 0 ;j--) {
				System.out.print(" ");
			}
			System.out.print("X");
			for(int j =  2 * i - 1 ; j > 0;j--) {
				System.out.print(" ");
			}
			System.out.print("X");
			System.out.println();
		}
		
	}
}	

Python :

n = int(input())
# 先画下半部分图形
m = n // 2 + 1
# 上半部分
for i in range(m, 1, -1):
    print(' ' * (m - i), end='')
    for j in range(1, 2 * i):
        if j == 1 or j == 2 * i - 1:
            print('X', end='')
        else:
            print(' ', end='')
    print()
# 下半部分
for i in range(1, m + 1):
    print(' ' * (m - i), end='')
    for j in range(1, 2 * i):
        if j == 1 or j == 2 * i - 1:
            print('X', end='')
        else:
            print(' ', end='')
    print()