array confusion

[torrinment]

Question about two peices of code
1. {
int i=0;
int j=0;
int total=0;
while(Character.isWhitespace(lines[i].charAt(j)))
{
total++;
i++;
j++;
}
return total;
this should show the number of characters in an already loadaded file but it doesnt

2How do you take a file with blank lines in it and crunch it up for example
this is

a file

now
should turn into

this
is
a file
now

[Uladzimir]

I)

int total=0;
for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
String str = lines[lineIndex];
if ( int j = 0; j < str.length; j++ ) {
if (!Character.isWhitespace(str.charAt(j))) { // if you do not want to calculate whitespaces
total++;
}
}
}


II)
BufferedReader br = new BufferedReader(XXX); // XXX - your input stream e.g. FileInputStream
String line;
while ((line = br.readLine()) != null) {
if (line.trim().size()str == 0) {
continue; // skip empty string
}
....
}

[torrinment]

Can you show it without continue and also your the first one doesnt work

[Uladzimir]

for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
String line = lines[lineIndex];
if (!line.trim().size() == 0) {
System.out.println(line);
...

}
}

[torrinment]

the character count one doesnt work either

{
int i=0;
int j=0;
int total=0;
while(Character.isWhitespace(lines[i].charAt(j)))
{
total++;
i++;
j++;
}
return total;

[Uladzimir]

The character count:

int total = 0;
String[] lines = new String[] {
"abcdef", "123", "qwer ty" // 15 chars + 1 space
};
for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
String str = lines[lineIndex];
for (int j = 0; j < str.length(); j++ ) {
if (!Character.isWhitespace(str.charAt(j))) { // if you do not want to calculate whitespaces
total++;
}
}
}
System.out.println(total);

[torrinment]

do you know what a nullpointer exception is

[Uladzimir]

Second example:

String[] lines = new String[] {
"this", " ", "is", "a" , " ", "test" };
for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
String line = lines[lineIndex];
if (!(line.trim().length() == 0)) {
System.out.println(line);
}
}


PS: I often post a programs which I don't check. I think small errors like misprints you can correct yourself.

[Uladzimir]

do you know what a nullpointer exception is

Yes I know. It happens when you try to do with something that don't exsists.

For example:
String s = null;
s.trim(); // throws NullPointerException

[torrinment]

that works but gives me a nullpointerexception how do i fix this like it does what it supposed to but then i get that exceptio n

[Uladzimir]

that works but gives me a nullpointerexception how do i fix this like it does what it supposed to but then i get that exceptio n

It's difficult to answer because I don't know your code. Please attach a whole your application or am exception stack trace.

BTW: check that you nowhere set empty values to variables.

[torrinment]

no im just talkin about both the character count you showed me and the eliminate vspace
public static int charCount(String[]lines)
{
int total = 0;
for (int i=0; i < lines.length; i++)
{
for (int j = 0; j < lines[i].length(); j++ )
{
if (!Character.isWhitespace(lines[i].charAt(j))) {
total++;
}
}
}
System.out.println(total);
return total;
}

and
public static void EliminateVSpace(String[]lines)
{
for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
String line = lines[lineIndex];
if (!(line.trim().length() == 0)) {
System.out.println(line);
}
}
}

[Uladzimir]

I understand. The exception happens because you pass lines with empty values.
For example
if you pass such array:
String[] lines = new String[] {"this", " ", "is", null, "a", "test" };
it will produce an exception.

[torrinment]

so i fix it by...