CHecking to see if a string can be casted to a char?

[okiiyama]

after,

line = reader.readLine();

I want to see if the user typed in an integer, anything else typed in can be disregarded.

i.e
Type Something: dk39ko3 <---(That would be disregarded)
Type Something: 3322.87 <---(That would be disregarded)
Type Something: hello <---(That would be disregarded)
Type Something: 11245 <---(This would be an int)
Type Something: 11234e <---(That would be disregarded)

What can I use that will take a string then go character by character to see if I have all digits (no letters).

I ideas would be greatly appreciated.

 

[djam]

here is a thought

find the length of the string
do this while loop
notFound = True


while (notFound && (index < line.length())
// use charAt to return the character at the specified
// index in the string

// use isDigit to check the character
// if it is a digit then notFound = false
// if it is not a digit index++
// the while loop will terminate if notFound = false or if you have checked the whole string
&quot;so many events, so little time&quot;

 

[djam]

opps sorrie, the while loop is wrong for you problem,

change the part where is said
&quot;if it is a digit then notFound = false&quot;

instead
&quot;if it is NOT a digit then notFound = false&quot;

&quot;so many events, so little time&quot;

 

[jbourne68]

this class will compile and run and do what you want
I think,

public class ContainsOnlyInts
{
public static void main (String[] args)
{
boolean onlyInts = true;
checkValues: // Used to end
if ( args.length == 1 )
{
byte[] chars = args[0].getBytes();
for ( int i=0; i < chars.length ; i++)
{
byte value = chars;
// 48 == 0 and 57 == 9 in ascii
// you can use unicode also
if ( value > 57 || value < 48)
{
// 10 == newline
if ( value != 10)
{
onlyInts = false;
}
break checkValues;
}
}
}
else
{
System.err.println(&quot;Please enter 1 value&quot;
onlyInts = false;
}
if (onlyInts)
{
System.out.println(&quot;Value entered contained only ints&quot;
}
else
{
System.out.println(&quot;Values did not contain only ints&quot;
}
}
}

 

[jbourne68]

sorry the line
byte value = chars;
should be char[j] with the j really being an i

I guess that is the how the software parses these posts
treats italics

 

[pedrosolorzano]

Hi okiiyama:

Check this easy solution:

public boolean validate(String s){
try{
Integer.parseInt(s);
}
catch(NumberFormatException e){
System.out.println(&quot;This is NOT an integer -->&quot;+s);
return false;
}
System.out.println(&quot;This is an integer -->&quot;+s);
return true;
}


Hope it helps. By the way, excellent codes those above. Pedro Andrés Solorzano
Pontificia Universidad Javeriana
Bogotá, Colombia, SurAmérica.

 

[okiiyama]

A user will be entering in a &quot;ip address&quot; xxx.xxx.xxx. Its not a real Ip address where the numbers can be greater than 255 and there doesn't need to be two decimals. Right now I have it where the tokenizer breaks the string down into the parts seperated by decimals. Now from there I just need to make sure there are no letters in each token, and also make sure that there are no &quot;..&quot; in the string.

I need to validate the user's 'ip string' to make sure it is a possible Ip String.

Possible 'Ip Strings'
12.3
1.2.3
122.55.667
999.999.999 (no token can be greater than 999)
so, I need at least one decimal, but no more then 2.

I think Pedro so far is the closest, but maybe I can get help in how to limit the user's input would be great as well...

Thank yOu so far for your help.

Josh