关于#属实#的问题,如何解决?

这个咋做,属实不会

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#include 
int main()
{
    int a , i , j ;
    scanf ( "%d" , &a ) ;
    for ( j = 1 ; j <= a ; j + 2 )
    {
        for ( i = 1 ; i <= j ; i++ )
    {
        printf( "*" ) ;
    }
    printf( "\n" ) ;
    }
    return 0;
}

#include <stdio.h>
int main()
{
    int a , i , j ;
    scanf ( "%d" , &a ) ;
    for ( j = 1 ; j <= a ; j += 2 )
    {
        for ( i = 1 ; i <= j ; i++ )
    {
        printf( "*" ) ;
    }
    printf( "\n" ) ;
    }
    for ( j = a - 1 ; j <=1 ;j -= 2 )
    {
        for ( i = 1 ; i <= j ; i++ )
    {
        printf( "*" ) ;
    }
    printf( "\n" ) ;
    }
    return 0;
}