unsigned long distribution[128] = { 0 } ;

int main( void )
{
    srand( time( 0 ) ) ;
        
    unsigned long total = 10000000 ;
    for( unsigned long count = 0 ; count < total ; count++ )
    {
        int r=rand()%62 ;
        r+=r>9?r>35?61:55:48 ;
        distribution[r]++ ;
    }
    
    for( int index = 0 ; index < 128 ; index++ )
    {
        printf( "%d %c %lu\n" , index , index , distribution[index] ) ;
    }
}