Changing Case of char Array

Using Arduino Programming Questions
7

Mr. "Smoke":

Below is how I tested your suggestion to UpCase a string.
Works good.
Doesn't look very good.
Can you suggest how I can get rid of the for loop and replace it with a while (myString != NULL) ?
I don't see how to step through the buffer without an index like "i".

Thanks.
Bob W.

char myString[] = "Hello";

void setup() {
  Serial.begin(9600);
  for (int i = 0; i < 100; i++ )  // 100 set arbitrarily and excessively large
  {
    if ( myString[i] == NULL ) break;
    myString[i] = myString[i] & 0b11011111;
  }

  Serial.print( &myString[0] );

GoForSmoke:
For the ASCII alphas, bit 5 is the difference in case.

1 loop the length of the buffer with break on NULL, if the ASCII is not alpha-only then with a range check ( data & 0xDF >= 'A' ) && ( data & 0xDF <= 'Z' ) and either set or clear bit 5.... make the state an arg and 1 function could do both change to upper or lower case.

And you don't need string.h to do that.