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asked on

string without first and last character challenge

Hi,

I am trying below challenge
http://codingbat.com/prob/p130896

i worte as below

public String withoutEnd(String str) {
int i=str.length();
if(i>=2)
return str.substring(1,2)+str.substring(2,i-1);
  
}

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i am getting error as below

Compile problems:


Error:      public String withoutEnd(String str) {
                    ^^^^^^^^^^^^^^^^^^^^^^
This method must return a result of type String

Possible problem: the if-statement structure may theoretically
allow a run to reach the end of the method without calling return.
Consider adding a last line in the method return some_value;
so a value is always returned.

please advise on how to fix and improve my code. Thanks in advance
Avatar of gudii9
gudii9
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ASKER

public String withoutEnd(String str) {
int i=str.length();
String str2=null;
if(i>=2){
str2= str.substring(1,2)+str.substring(2,i-1);
}
return str2;
  
}

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i tried as above still test cases failing

Expected      Run            
withoutEnd("Hello") → "ell"      "ell"      OK         
withoutEnd("java") → "av"      "av"      OK         
withoutEnd("coding") → "odin"      "odin"      OK         
withoutEnd("code") → "od"      "od"      OK         
withoutEnd("ab") → ""      "Exception:java.lang.StringIndexOutOfBoundsException: String index out of range: -1 (line number:5)"      X         
withoutEnd("Chocolate!") → "hocolate"      "hocolate"      OK         
withoutEnd("kitten") → "itte"      "itte"      OK         
withoutEnd("woohoo") → "ooho"      "ooho"      OK         
other tests
OK       

please advise
Avatar of ozo
What is "ab" without the first and last character, and how can you return it without giving substring an out of range index?

You might also think about whether there is a better way to write
str.substring(1,2)+str.substring(2,i-1)
Avatar of gudii9

ASKER

What is "ab" without the first and last character, and how can you return it without giving substring an out of range index?

without first and last character "ab" is nothing so i got above error which make sense now.

"The string length will be at least 2. "

Above line given in problem challenge. Does that mean 2 is included or no(i mean string leght should be 3 or more)??
You might also think about whether there is a better way to write
str.substring(1,2)+str.substring(2,i-1)

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i am still thinking to write in better way
Avatar of gudii9

ASKER

public String withoutEnd(String str) {
int i=str.length();
String str2=null;
if(i>2){
str2= str.substring(1,2)+str.substring(2,i-1);
return str2;
}

else
{
return "";
}
  
}

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i modified as above and passing all tests. Does it look fine? please advise
What you wrote works.
But there is a simpler way to do it.
Avatar of gudii9

ASKER

But there is a simpler way to do it.
can you please let me know?
If you simplify
str.substring(1,2)+str.substring(2,i-1);
then some other complications may also become unnecessary.
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ASKER

If you simplify
str.substring(1,2)+str.substring(2,i-1);
how to simplify. i am not getting better idea. please advise
How did you choose the number 2?
Avatar of gudii9

ASKER

return a version without the first

In the challenge they said as above without first character so i choose 2 to start from 2nd
Avatar of gudii9

ASKER

public String withoutEnd(String str) {
int i=str.length();
String str2=null;
if(i>2){
str2= str.substring(1,i-1);
return str2;
}

else
{
return "";
}
  
}

Open in new window


I think i got what you meant. I was able to modify as above and able to pass all the tests. Is my code in right track?
On the right track.
Would
str.substring(1,i-1);
work in any other case besides
if(i>2){
?
Avatar of gudii9

ASKER

if i=2  then str.substring(1,i-1) become str.substring(1,1);//will not work as it looks string starting index 1 till 1 excluding 1
if i=1  then str.substring(1,i-1) become str.substring(1,0);//will not work as it looks string starting index 1 till 0 excluding 0
if i=0  then str.substring(1,i-1) become str.substring(1,-1);//will not work as it looks string starting index 1 till -1 excluding -1
if i=2  then str.substring(1,i-1) become str.substring(1,1);//will not work as it looks string starting index 1 till 1 excluding 1
false

if i=1  then str.substring(1,i-1) become str.substring(1,0);//will not work as it looks string starting index 1 till 0 excluding 0
true

if i=0  then str.substring(1,i-1) become str.substring(1,-1);//will not work as it looks string starting index 1 till -1 excluding -1
true
Avatar of gudii9

ASKER

if i=2  then str.substring(1,i-1) become str.substring(1,1);//will not work as it looks string starting index 1 till 1 excluding 1
false

i wonder why it is false.

How ti looks for string starting index 1 till index 1 excluding index 1.
please advise
What is the length of substring(1,i-1) ?
What is 1-1?
Avatar of gudii9

ASKER

Length I am thinking as 0
yes
Avatar of gudii9

ASKER

if i=2  then str.substring(1,i-1) become str.substring(1,1);//will not work as it looks string starting index 1 till 1 excluding 1
false

I wonder why above answer is false. I am still thinking it will not work. please advise
the
it looks string starting index 1 till 1 excluding 1
part is true,
the
will not work
part is false

What is the length of the string you want to return if i==2?
Avatar of gudii9

ASKER

What is the length of the string you want to return if i==2?
0
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ASKER

so it simply prints empty string if i==2?
As required.
Avatar of gudii9

ASKER

if i=2  then str.substring(1,i-1) become str.substring(1,1);//will not work as it looks string starting index 1 till 1 excluding 1

i have to correct as
if i=2  then str.substring(1,i-1) become str.substring(1,1);//will  work as it looks string starting index 1 till 1 excluding 1
Avatar of gudii9

ASKER

i have to correct as
if i=2  then str.substring(1,i-1) become str.substring(1,1);//will  work as it looks string starting index 1 till 1 excluding 1

and prints "".

I am correct in my understanding right?
please advise
ASKER CERTIFIED SOLUTION
Avatar of ozo
ozo
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