Java with BlueJ, 2016a

50 CHAPTER 2. BASICS
method charAt(...) returns the character at a specific position to the point
where the method is invoked. The method charAt(...) must always have
an argument value (the position) passed to it. For Java, positions within a
string begin at 0 and so the first hyphen should be at position 3. Note in
the program, at line 9, shown here:
char firstHyphen = sin.charAt(3);
how the method is invoked (a period separates the name of the string, sin,
from the name of the method) and how the value 3 is passed to the method
(in parentheses as an argument value).
Listing 2.10: Obtaining a character within the string at a specific position
1 public class UsingStringCharAt
2 {
3 public static void main(String[] args)
4 {
5 // variable password is of type String
6 // variable passwordLength is of type int
7 String sin = "123-987-555";
8 // use the charAt() method
9 char firstHyphen = sin.charAt(3);
10 // Display the string and
11 // the character in position 3
12 System.out.println("SIN is");
13 System.out.println(sin);
14 System.out.println("character at position 3
is");
15 System.out.println(firstHyphen);
16 }
17 }
Figure 2.6: Showing the string and the character at position 3