帮忙设计一个简单C语言程序

#include<stdio.h>
#include<stdlib.h>

int main ()
{
char s[10]="abcdef";
char *px=NULL,*py=NULL,*ppx=NULL,*ppy=NULL;
px=s;
py=s;
ppx=s;
ppy=s;
char y;
printf("THE s is :%s ",s);
y=*px++;
printf("\nTHE y=*px++ y is :%c ",y);
y=*ppy--;
printf("\nTHE *ppy-- y is :%c ",y);
y=*++py;
printf("\nTHE y=*++py y is :%c ",y);

(*py)++;//*py为py所指向的值。然后值++
printf("\nTHE s after (*py)++ is :%s ",s);

y=--*ppx++ ;
printf("\nTHE y=--*ppx++ y is :%c ",y);
printf("\nzifu a-1=%c",'a'-1);
printf("优先级顺序 ++ * --");
return 0;
}