String, Scanner

String Concatenation

joins together two or more strings end-to-end to make a new string.

ex: "Hello" + "CMSC131" --> "HelloCMSC131"

When a string is concatenated with another type, the other type is first evaluated and converted into its string representation

ex: (1+2) + "5" --> 35

string comparison

strings can not be compared using the opperators (==, <=, <. etc)

s.equals(t)

returns true if the s equals t

s.length()

returns length

s.compareTo(t)

compares strings lexicographically (dictionary order)

result < 0 if s is less than t

result == 0 if s is equal to t

result > 0 if s is greater than t

Scanner

allows users to input values

you MUST import a library before using scanner

importing a scanner library

import java.util.Scanner;

create a scanner object

new Scanner(input_source);

must be assigned to a variable

ex:
scanner = new Scanner(System.in);

scanner operations

scanner.nextBoolean()
scanner.nextByte()
scanner.nextDouble()
scanner.nextFloat()
scanner.nextInt()
scanner.nextLong()
scanner.nextShort()

next()

Returns sequence of characters up to next whitespace (space, carriage return, tab, etc.)

nextLine()

Returns sequence of characters up to next carriage return

reads the next character

char symbol = scanner.next().charAt(0);