Java String Assignments -intro-1

Java String Assignments

These exercises are introductory methods that require use of basic String methods including

  • substring()
  • length()
    • “abc”.length() – >3
  • concatenation


public boolean sameStrings(String string1 ,String string2)

Description: This method returns true if string1 and string2 are the same. Use the ‘.equals()’ method.

Method Call return value/output
sameStrings(“foo”,”f”) false
sameStrings(“foo”,”foo”) true
sameStrings(“abc”, “cba”) false

public boolean any2Same(String a,String b, String c)

Description: This method returns true if any 2 of the strings are the same. Remember: Use the ‘.equals()’ method.

Method Call return value/output
any2Same(“xz”,”f”, “xz”) true
any2Same(“xz”,”f”, “xt”) false
any2Same(“xz”,”xz”, “fff”) true
any2Same(“xtz”,”abc”, “abc”) true
any2Same(“xtz”,”a^c”, “a!c”) false

public String firstThirdLettters(String str)

Description: This method returns the first and third letters of str concatenated together.

Method Call return value/output
firstThirdLettters(“foo“) “fo”
firstThirdLettters(“abcdefg”) “ac”
firstThirdLettters(“ad!kjkj”) “a!”

public boolean sameFirst2Letters(String a, String b)

Description: This method returns the first 2 letters of a and of b are the same .

Method Call return value/output
sameFirst2Letters(“axt”, “axjjj”) true
sameFirst2Letters(“1%3″ , “3$1″) false
sameFirst2Letters(“a~dd” ,”~adt” ) false

public String concatTwice(String str)

Description: This method returns str concatenated with itself .

Method Call return value/output
concatTwice(“foo”) “foofoo”
concatTwice(“a”) “aa”
concatTwice(“abcdd”) “abcddabcdd”

public String concatWithComma(String str)

Description: This method returns str concatenated with itself and with a comma in between

Method Call return value/output
concatWithComma(“foo”) “foo,foo”
concatWithComma(“a”) “a,a”
concatWithComma(“abcdd”) “abcdd,abcdd”

public String sandwich(String bread, String meat)

Description: This method is easiest to understand by looking at the sample calls below

Method Call return value/output
sandwich(“a“,”b“) aba
sandwich(“xy“,”ab“) xyabxy
sandwich(“hi“,”bye“) hibyehi

public int lengthTimesTwo(String str)

Description: This method returns the length of str times 2.

Method Call return value/output
lengthTimesTwo(“foo”) 6
lengthTimesTwo(“a”) 2
lengthTimesTwo(“abcdd”) 10

 String prePendFoo(String str)

Description: prepend “foo ” to the input and return the concatenation.

Method Call return value/output
prePendFoo(“abc”) “foo abc”
prePendFoo(“x”) “foo x”
prePendFoo(“abcdd”) foo abcdd”

public int sumOfLengths(String a, String a)

Description: This method returns the sum of the lengths of String a and String b .

Method Call return value/output
sumOfLengths(“ab”, “jk1”) 5  ie ( 2 +3)
sumOfLengths(“jj”, “”) 2 (ie 2 + 0)
sumOfLengths(“a~dd” ,”6″ ) 5  ie ( 4  + 1)

**public String concat5Times(String str)

Description: This method returns str concatenated with itself 5 times (Do this with a loop)

Method Call return value/output
concat5Times(“foo”) “foofoofoofoofoo”
concat5Times(“a”) “aaaaa”
concat5Times(“abcdd”) “abcddabcddabcddabcdd”