const uint32_t png_ihdr = 'IHDR';

char c = 'x';
char *s = "Hello World";

char myChar     = 'A';
char myString[] = "Hello Mum";
char myOtherString[] = { 'H','e','l','l','o','' };

printf("%d %d", 'c', 'cc'); would give:

char str[] = "Hello world";

char c = 'x';

printf("%c n",'a');
 printf("%s","Hello World");

printf("%c n","a");
  printf("%s",'Hello World');

char ch = 'a';

char str[] = "foo";