Binary value of char *

Using Arduino Programming Questions
#1

Does anyone know how to set the binary value of a char pointer? (ikr :astonished: :grin:)
Basically what I would like to do is use an integer to set the binary value of a char* and increment the value of the integer thus changing the char* value progressively. I understand that the application of this may seem totally wacko, but I am in a very unique situation who's explanation would go far beyond satisfying your curiosity and trying my writer's-patience.

#2

Assign the value that you want cast into a char*?

foo = (char*)55

Not sure if that would work, though.

#3

If it compiles...

char* whatever;
char buffer[2];

void setup( void )
{
  whatever = &buffer[0];
}

void loop( void )
{
  ++(* (int*) whatever);
}
#4

marco_c, I tried typecasting, but to no avail.
Coding Badly, that worked! Thanks!

#5

Basically what I would like to do is use an integer to set the binary value of a char* and increment the value of the integer thus changing the char* value progressively

A dereferenced char * pointer is a short (8bit) form of integer, so you can do math on it directly.
The following sketch will print “Aest Best Cest … Zest”

char *s = "sest";
void setup() {
 serial.Begin(9600);
 *s = 65;   //  Note 65 == 'A'
  serial.Println(s);
}
void loop() {
  if (*s < 'Z') {   // Check whether we reached the end of the alphabet
   *s += 1;   // Increment the first letter of the word to next value
   Serial.println(s);
  }
}

You can also access pointers as arrays. Adding “s[1] += 1;” to the above at some point would result in “Afst”
Note that *s++ increments the pointer rather than the thing pointed to. You could say “(*s)++;”

#6

fuzzball27:
Does anyone know how to set the binary value of a char pointer? (ikr :astonished: :grin:)

The pointer holds an address in memory. You can change the pointer with math. If it is a byte pointer then adding 1 to that pointer will address the next byte, subtracting 1 gets the one before. And if it's an int pointer then the address moves by ints. The best way to set the address is to make it = myarray, the name without brackets that points to myarray[0]. Your compiler handles where that actually is in memory while it's in scope.

[/quote]Basically what I would like to do is use an integer to set the binary value of a char* and increment the value of the integer thus changing the char* value progressively. I understand that the application of this may seem totally wacko, but I am in a very unique situation who's explanation would go far beyond satisfying your curiosity and trying my writer's-patience.
[/quote]

Read up on pointers and pointer math. Also on pre-increment and post-increment operators.

#7