Week 2: Methods, strings and lists/10a Strings

Java has variables of reference type.
In a reference type variable, the variable is placed in reference to the actual value. 

String b = "bye!";
- immutable
- but can point to another string


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String name = "Jack Java";
String address = "Java rd. " + "64" + ", 12345, Javatown";
String phonenum = "040-" + (12345 * 23456); //multiply, then concat as strings
System.out.println(name);
System.out.println(address);
System.out.println(phonenum);

Program outputs:
Jack Java
Java rd. 64, 12345, Javatown
040-289564320




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String length - .length()


String first = "Hey";
System.out.println(first.length());

System.out.println("Hello everyone".length());

int length = (first + "!!!").length();
System.out.println(length);


Program outputs:
3
14
6



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single characters - charAt(i)

Scanner reader = new Scanner(System.in);
System.out.print("Give a string: ");
String str = reader.nextLine();

for (int i=0; i<str.length(); i++) {
    System.out.println(str.charAt(i));
}
 

Program outputs:
Give a string: Test
T
e
s
t








// returns a 'character' - which is a number type
char first = 'O';
char second = 'k';
System.out.println(first + second);

Program outputs:
186



// A character can be converted into a string
// 1 either by using the method toString in the Character class
char cr = 'X';
String str = Character.toString(cr);

Program outputs:
X


// 2 or usually more easily by CONCATenating a character with an EMPTY STRING:
char first = 'O';
char second = 'k';
System.out.println("" + first + second);

Program outputs:
Ok

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