Comparing a string to int

lad12

Can anyone tell me how to compare a string to an int...or is it possible...

aidan_walsh

How do you mean?

"10" to 10?
"Ten" to 10?

What language are you using?

Kernel32

Of course its possible, generally through a data conversion or type casting. The mechanics of how you do it will depend on the language in question, seeing as you did not provide any information about which language then I can't give any decent answer.

lad12

It's in java

i want to compare a string to an int

if(string = 0)

the compareTo method only woks for strings and .equals only works for int's i think...is there anyway around this..

aidan_walsh

You'll need to wrap the int in an Integer class.

if(yourString == Integer.valueOf(int))

.compareTo and .equals both only work for Objects. Numeric operators (==, !=, etc) only work for primitive types.

lad12

So will this work...

if(Input == Integer.valueOf(0))

egan007

Originally posted by lad12
It's in java

i want to compare a string to an int

if(string = 0)

the compareTo method only woks for strings and .equals only works for int's i think...is there anyway around this..

What are you trying to do - if i may ask

why has your string a number?

or
are you trying to see if the srting is empty or equal to NUll i.e =" "

aidan_walsh

What am I saying...

It should be:

if(Input.equals(Integer.valueOf(0))

He he he... Brains a bit frazzled after looking at C# all day...

lad12

I want to check if the input from the user is an number...if it is a number then i want the program to finish

and the input is supposed to be a string...but if the user inputs a certain number then it should end

Imposter

if(Integer.parseInt(myString) == myInt)

is what you need.

lad12

What am I saying...

It should be:

if(Input.equals(Integer.valueOf(0))

He he he... Brains a bit frazzled after looking at C# all day...
___________________________________________________________

Yeah something like that

Enygma

If you're doing that you should probably convert the string the user entered into a number first

int num = Integer.parseInt(userInput);
if (10 == num)
{
   // return 
}

Imposter

Of course you will also have to catch a NumberFormatException should something other than a number be entered.

lad12

and...

egan007

Originally posted by lad12
I want to check if the input from the user is an number...if it is a number then i want the program to finish

and the input is supposed to be a string...but if the user inputs a certain number then it should end

Here is a nice clean way

getText() - get ur string
charAt(0) - cut off the first character
isDigit() - see if it's a number
isLetter() - or a letter

Karoma

and what? they've answered it for you..



--Edit:
Regular Expression:
if user input is of: regex:[ 0 - 9 ]+ then system.exit..
else ..keep going or whatever

lad12

No they aint cos im getting an error in my program...

Karoma

what error? post it up. They have answered your question.

aidan_walsh

Care to enlighten us?

Post both your code and the error... otherwise its a little hard to help.

egan007

ok - well i'm in a good mood so ....


String s = myTextFiled.getText();
boolean isNumeric = true;

try {
Integer.parseInt(s);
}
catch (NumberFormatException nfe) {
isNumeric = false;
}

if (isNumeric) {

//do numeric work for s
}
else {
//do alphanumeric work
}


i better get my name hashed in

lad12

But is there just a method i can use

like ive ive tried

int num = Integer.parseInt(userInput);

and

if(Input.equals(Integer.valueOf(0))

oh and how can i get a program to terminate using an if statement...i know using a while statement i can use break...

aidan_walsh

Originally posted by lad12
But is there just a method i can use

Unless you write it yourself... No, no there is not...

Just post your code and the error you get or the returned stack trace and we'll take a look and tell you whats up...

egan007

Originally posted by lad12
But is there just a method i can use

like ive ive tried

int num = Integer.parseInt(userInput);

and

if(Input.equals(Integer.valueOf(0))

oh and how can i get a program to terminate using an if statement...i know using a while statement i can use break...

check previous page

lad12

It's grand..thanks for yer Help...

Karoma

egan007 + exitingfeature:

String s = myTextFiled.getText(); // get the user input
boolean isNumeric = true; // true if input is a number

try 
{
  int newInt = Integer.parseInt(s); // convert String to int
}
catch (NumberFormatException nfe) 
{ //catch errors when converting..
  isNumeric = false; // and tell everything else that it is _not_ a number
}

Exit when input "is a number" :

if (isNumeric) 
{
  System.exit(0);  // exit!
}
else 
{
//do alphanumeric work
}

exit if input is a specific number :

if (newInt == 1) 
{  //replace 1 with whatever number to test. to test against more than one num:
   // if (newInt == 1 || newInt == ....)
  System.exit(0);  // exit!
}
else 
{
//do alphanumeric work
}

egan007

the code is there - what do you want - us to run it?

i could not of written it any clearer

Karoma

//declare vars
int newInt;

//------------ pass in a string and get an int back
public int smellyStringToInt(String in_userInput)
{
  try
  {
    newInt = Integer.parseInt(String in_userInput);
  }
  catch(NumberFormatException nfe)
  { //error message }

  return newInt;
}

//-----------------------------------

now: to convert userinput to an int:

smellyStringtoInt( textfield.getText() );

public boolean compareTwoInts(int in_WhatTocheckAgainst, int in_convertedInt)
{
  boolean isMatch;

  if ( in_WhatTocheckAgainst ==  in_convertedInt)
  {//they match
    isMatch = true;
  }
  else
  {//not a match
    isMatch = false;
  }

  return isMatch;
}

compareTwoInts(intToCheckFor , newInt );

i get the feeling the assignment asked you to create methods to do it
post up the assignment... (not saying that i'll do it)

lad12

Yeah i got it working...thanks for all yer help