#include<iostream>

int main()
{
    using namespace std;
    int m,i,j,k;
        cout<<"Please input rows:"
    cin>>m;
    for(i=1;i<=m;i++)
    {
        for(j=1;j<=m-i;j++)
            cout<<" ";
        k=2*i-1;
        for(j=1;j<=k;j++)
            cout<<"*";
            
        cout<<endl;
    }
    return 0;
}
但实现不了，要求的：
   *
 *   *
*     *

  *
 * *
*   *

怎么打不出来，就是内层是空的、、、

这样？

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

int main( void )
{
    unsigned n;
    cout << "Please input rows:";
    cin >> n;

    cout << setw(n+1) << "*\n";
    for( unsigned i=1; i!=n; ++i )
        cout << setw(n-i)<<'*' << setw(2*i+1)<<"*\n";

    return 0;
}

用C语言写一个

#include <stdio.h>

int main( void )
{
    unsigned n;
    printf( "%s", "Please input rows:" );
    scanf( "%u", &n );

    for( unsigned i=0; i!=n*2*n; ++i )
    {
        if( i%(2*n)==i/(2*n)+n )
            putchar( '\n' );
        else if( i%(2*n)<i/(2*n)+n && (i%(2*n)+i/(2*n)+1==n || i%(2*n)+1==i/(2*n)+n) )
            putchar( '*' );
        else if( i%(2*n)<i/(2*n)+n )
            putchar( ' ' );
    }

    return 0;
}

#include <stdio.h>

int main( void )
{
    unsigned n;
    printf( "%s", "Please input rows:" );
    scanf( "%u", &n );

    printf( "%*c\n", n, '*' );
    for( unsigned i=1; i!=n; ++i )
        printf( "%*c%*c\n", n-i, '*', 2*i, '*' );

    return 0;
}

你要是这样的结果？