Transcript Introduction to Programming With Java

“Introduction to Programming
With Java”
Lecture - 11
UMESH PATIL ([email protected])
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Contents for Today’s Lecture
• Programming practice: Program for morphological
analysis of English nouns.
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Problem
Write a Java program that finds out the root & suffix of the given noun
plural in English. Also print the morphology rule applied for forming
the plural.
Sample input & output –
Input: boys
Output:
root = boy
suffix = s
Morphology rule = [[W]]  [[W][s]]
Input: indices
Output:
root = index
suffix = ices
Morphology rule = [[W][ex]]  [[W][ices]]
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Plurals in English
Example
Morphology Rule
•
boy  boys
•
W  Ws
•
bus  buses
•
W  Wes
•
lady  ladies
•
Wy  Wies
•
leaf  leaves
•
Wf  Wves
•
datum  data
•
Wum  Wa
•
formula  formulae
•
W  We
•
index  indices
•
Wex  Wices
•
matrix  matrices
•
Wx  Wces
•
radius  radii
•
Wus  Wi
•
cherub  cherubim
•
W  Wim
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Algorithm
1. Read the input word
2. Find the suffix
3. Remove suffix & get the root
4. If needed, prepare the correct root
eg. indices  ind  ind + ex = index
5. Print the output
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Required Methods of String class
1. boolean endsWith(String suffix)
Returns true if the string ends with the specified suffix;
false otherwise.
Parameters: the String suffix.
eg. If s = “indices” then
s.endsWith(“ices”) will return true
s.endsWith(“s”) will return true
s.endsWith(“”) will return true
s.endsWith(“indices”) will return true
But
s.endsWith(“ice”) will return false
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Required Methods of String class… continued
2.
String substring(int beginIndex, int endIndex)
Returns a new string that is a substring of the current string. The
substring begins at the specified beginIndex and extends to the
character at index endIndex - 1. It will give error (throw exception) if
the beginIndex is negative, or endIndex is larger than the length the
string, or beginIndex is larger than endIndex.
Parameters:
beginIndex - the beginning index, inclusive.
endIndex - the ending index, exclusive.
eg. If s = “mississippi” then
s.substring(0,4) will return “miss”
s.substring(6,9) will return “sip”
s.substring(0,11) will return “mississippi”
s.substring(0,0) will return “”
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Required Methods of String class… continued
3. int lastIndexOf(String str)
Returns the index within the current string of the
rightmost occurrence of the specified substring. If str does
not occur as a substring, -1 is returned.
Parameters: str - the substring to search for.
eg. If s = “mississippi” then
s.lastIndexOf(“is”) will return 4
s.lastIndexOf(“i”) will return 10
s.lastIndexOf(“”) will return 11
s.lastIndexOf(“mississippi”) will return 0
And
s.lastIndexOf(“abc”) will return -1
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Required Methods of String class… continued
4. String concat(String str)
Returns a string after concatenating the specified string, ie.
str, to the end of the current string.
Parameters:
str - the string that is concatenated to the end of the current
string.
eg. if s = “man” then
s.concat(“go”) will return “mango”
s.concat(“”) will return “man”
Detailed explanation of the String class.
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Core Part of the Program
Suppose input word = “indices”;
if (word.endsWith("ices")) {
// word = “indices”
suffix = "ices";
i = word.lastIndexOf("ices"); // i = 3
root = word.substring(0,i);
// root = “ind”
root = root.concat("ex");
// root = “index”
morphRule = "[[W][ex]]  [[W][ices]]";
}
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Some Testing
1. matrix  matrices
2. life  lives
3. analysis  analyses
4. criterion  criteria
Does the program work for these examples?
If yes, how?
If no, why?
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Assignment
1. Do the morphological analysis of the following inflected verbs
in English and write a Java program that finds out the root &
suffix of the given inflected verb. Also print the morphology
rule that is applied.
fetch  fetches, fetching, fetched
carry  carries, carrying, carried
enjoy  enjoys, enjoying, enjoyed
burn  burns, burning, burnt
beat  beats, beating, beaten
forbid  forbids, forbidding, forbided, forbidden
blow  blows, blowing, blowed, blown
save  saves, saving, saved
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Assignment … continued
say  says, saying, said
drop  drops, dropping, dropped
admit  admits, admitting, admitted
repel  repels, repelling, repelled
dog  dogs, dogging, dogged
can  cans, canning, canned
spur  spurs, spurring, spurred
stem  stems, stemming, stemmed
stab  stabs, stabbing, stabbed
kid  kids, kidding, kidded
mimic  mimics, mimicking, mimicked
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To Remind
The best way to learn programming
is writing a lot of programs on your
own.
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End
Thank you 
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