// APS101, Winter 2009: Lecture 18 (Feb. 24)
//
// Review:
//
// if-statements
//
// if (boolean-expression) {
//    then-part;
// } else if (another boolean-expression) {
//    else if-part;
// } else {
//    else-part;
// }
//
// - can have many "else if" parts, but only one "else"
//
// while loops
//
// while (termination condition) {
//    do something;
// }
//
// two possible problems:
//    - infinite loops (it never terminates)
//    - no loop (the termination condition is false from the start)
//
// PRACTICE WITH IF-STATEMENTS
//
// we wrote the Grades class, with method passFail
Grades.passFail(0.1)
Grades.passFail(98)
Grades.passFail(100)
Grades.passFail(0)
Grades.passFail(50)
Grades.passFail(49)
Grades.passFail(1)
Grades.passFail(-1)
Grades.passFail(200)

// then, we wrote method letterGrade, which prints the letter corresponding to the grade.
// here is the letter grade scheme:
// g >= 90 -> "A+"
// g >= 80 and g < 90 -> "A"
// g >= 70 and g < 80 -> "B"
// g >= 60 and g < 70 -> "C"
// g >= 50 and g < 60 -> "D"
// g < 50 -> "F"
Grades.letterGrade(55)
// what other values should you test?
// 0, 50, 51, 60, 61, 70, 71, 80, 81, 90, 91, 100
//
// For Assignment 2 you will need to process Strings by splitting them into "tokens"
// Tokenization: breaking a String into several parts (words, typically). 
// Ex. "This is a test."
// This
// is
// a
// test
// .      // this is only if we treat punctuation as separate tokens! (which we usually don't)

import java.util.StringTokenizer;
StringTokenizer st = new StringTokenizer("This is a test.")
st.nextToken()
st.nextToken()
st.nextToken()
st.nextToken()
st.nextToken() // error! no more tokens.

// delimiter: a character that separates the tokens
// default delimiters: " \t\n\r\f"
// \t: tab
// \n: newline
// \r: carriage return (moves cursor to first position on line)
// \f: line feed (moves cursor down to next line)

StringTokenizer st = new StringTokenizer("This\tis\ta\ttest.")
st.nextToken()
st.nextToken()
st.nextToken()
st.nextToken()

StringTokenizer st = new StringTokenizer("This\t    is     a\ttest.")
st.nextToken()
st.nextToken()
st.nextToken()
st.nextToken()
st.nextToken()
// the number of spaces doesn't matter!

StringTokenizer st = new StringTokenizer("This is a test.")
// what if we want to see the number of available tokens?
st.countTokens() // = 4
st.nextToken()
st.countTokens() // = 3

StringTokenizer st = new StringTokenizer("This is a test.")
st.hasMoreTokens() // true
st.nextToken()
st.hasMoreTokens()
st.nextToken()
st.nextToken()
st.nextToken()
st.hasMoreTokens() // false!
st.countTokens() // = 0

StringTokenizer st = new StringTokenizer("This is a test.")

// what if we want to print out all the tokens?
while (st.hasMoreTokens()) {
    System.out.println(st.nextToken());
}

// how about all on one line? Use System.out.print (rather than prinln)
while (st.hasMoreTokens()) {
    System.out.print(st.nextToken());
}

// need to put a space in between words! 
while (st.hasMoreTokens()) {
    System.out.print(st.nextToken() + " ");
}

// what if we want to store all the tokens in one String variable?
String s = "";
StringTokenizer st = new StringTokenizer("This is a test.")

while (st.hasMoreTokens()) {
    s = s + st.nextToken() + " "; // we "build" the String, token by token
}
s

// what's the problem? (there's an extra space at the end of the String!)
// need to remove it...
s = s.substring(0, s.length() - 1)