Not sure in what environment your asking for, but in C programming, %d is an integer (basically a number), %c is a character, that is a single alphanumeric character, where as %s is a series of alphanumeric characters, in programming %s is actually just an array of characters (so multiple %c), but don't worry about that to much.
Examples in c.
int number = 1;
char character = "c"; (numbers (integers) can be characters)
char string[5] = "abcd"; ([5] implies 5 characters, here there are 4, that is because an invisible character exists known as a "null terminator" (\0).
