C/Pointers

A helper for people starting out with pointers:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
 
#define P(expr) printf("%10s: 0x%02X\n", #expr, expr)
 
int main(void) {
	char *s = "abc";
	char **p = &s;
 
	P(s);
	P(&s);
 
	P(s[0]);
	P(*s);
 
	P(p);
	P(&p);
	P(p[0]);
	P(*p);
 
	P(p[1]);
 
	P(*p[1]);
	P((*p)[1]);
	P(*(p[1]));
 
	P((*p));
	P((*p)++);
	P((*p)[0]);
	P((*p));
	P(++(*p));
	P((*p)[0]);
	P((*p));
 
	return 0;
}