How to write the alphabet in C with a loop?

The following codes display the 26 letters of the alphabet in C:

char c;

// Displays abcdefghijklmnopqrstuvwxyz
for (c='a'; c<='z' ; c++) printf ("%c", c);
  
// Displays ABCDEFGHIJKLMNOPQRSTUVWXYZ
for (c='A'; c<='Z' ; c++) printf ("%c", c);

Check this online example on repl.it.

The following codes display the 26 letters of the alphabet in C:

char c;

// Displays abcdefghijklmnopqrstuvwxyz
for (c='a'; c<='z' ; c++) printf ("%c", c);
  
// Displays ABCDEFGHIJKLMNOPQRSTUVWXYZ
for (c='A'; c<='Z' ; c++) printf ("%c", c);

Check this example online on repl.it.