fileSize help

[jonjon0688]

Using the countChars() method from the previous answer, write a method called fileSize() declared as follows:
public int fileSize (String name) {
...
}

which counts the number of characters in the file whose name is supplied as the "name" parameter. This method should return the number of characters in the file, or -1 if an IOException occurs.




public int fileSize(String name) throws IOException
{

try {
InputStreamRead er isr = new InputStreamRead er(new FileInputStream ("name"));
int charLength = 0;

while (isr.read() != -1)

charLength++;

return charLength;
}

catch (Exception e) {
return -1;
}
}

it always returns -1
any know where i am going wrong?

[JosAH]

Does a file named "name" in your current working directory exists? You can find
your current working directory from Java as follows:

[code=java]
System.out.prin tln("cwd: "+System.getPro perty("user.dir "));
[/code]

kind regards,

Jos

[jonjon0688]

But does the question not state that the file is called "name"? it would not matter whether i have the file or not when i submit my work.
Is it something to do with where i have placed try {

thanks for the help

[JosAH]

But does the question not state that the file is called "name"? it would not matter whether i have the file or not when i submit my work.
Is it something to do with where i have placed try {

thanks for the help

Nope, your method is supposed to take a String argument which is supposed to
be the name of a file. Not literally that the name of the file should be "name", i.e.
if you have a file named "fronobulax.foo " in your current working directory pass
that string to your method.

kind regards,

Jos

[jonjon0688]

is this what you mean ?

public int fileSize(String name) throws IOException
{

try {
InputStreamRead er isr = new InputStreamRead er(new FileInputStream (System.getProp erty("user.dir" )));

int charLength = 0;

while (isr.read() != -1)

charLength++;

return charLength;
}

catch (Exception e) {

return -1;
}
}

[JosAH]

No that's not what I mean, use the parameter 'name' (without quotes):

[code=java]
InputStreamRead er isr = new InputStreamRead er(new FileInputStream (name));
[/code]

All I wanted to say is that you have to supply a name of an existing file; otherwise
you get back -1 from that method which is what you complained about.

kind regards,

Jos

[jonjon0688]

this is what i have:

public int fileSize(String name) throws Exception
{

try {
InputStreamRead er isr = new InputStreamRead er(new FileInputStream ("name.txt") );

int charLength = 0;

while (isr.read() != -1)

charLength++;

return charLength;
}

catch (IOException e) {

return -1;

}
}

it is not returning the right number of characters?

[JosAH]

You're doing it again: the name of the file is supposed to be passed in the
parameter 'name' (without the quotes). All you do is try to open an file name.txt.
Don't do that; we'll get back to your logic error later.

kind regards,

Jos

[jonjon0688]

sorry i know im being really stupid, but i don't quite understand what you mean?

[r035198x]

sorry i know im being really stupid, but i don't quite understand what you mean?

Your method is always opening a file called name.txt. It is ignoring the parameter(calle d name) that is being passed. If I want to use it for my file called, say myFile.txt, it won't work because it is hardcoded to work only for a file called name.txt.

[jonjon0688]

Your method is always opening a file called name.txt. It is ignoring the parameter(calle d name) that is being passed. If I want to use it for my file called, say myFile.txt, it won't work because it is hardcoded to work only for a file called name.txt.

ok i understand, so what should i do?

[r035198x]

ok i understand, so what should i do?

In new FileInputStream ("name.txt") );

use the String parameter that is passed to your method instead of "name.txt".

You do know what a parameter is right?

[jonjon0688]

like this ..

public int fileSize(String name) throws IOException
{

try {
InputStreamRead er isr = new InputStreamRead er(new FileInputStream (name));
int charLength = 0;

while (isr.read() != -1)

charLength++;

return charLength;
}

catch (Exception e) {
return -1;
}
}

the error i get know is that it does not give the right output..

[JosAH]

the error i get know is that it does not give the right output..

What is the output and what should it be?

kind regards,

Jos

[r035198x]

like this ..

public int fileSize(String name) throws IOException
{

try {
InputStreamRead er isr = new InputStreamRead er(new FileInputStream (name));
int charLength = 0;

while (isr.read() != -1)

charLength++;

return charLength;
}

catch (Exception e) {
return -1;
}
}

the error i get know is that it does not give the right output..

Read your problem specs again. Aren't you supposed to use a certain method ...