# Thread: How can I determine the type of an input

1. ## How can I determine the type of an input

What I mean is this :
I have to write a program that gets an integer and prints it on the screen. Otherwise, an error message should be printed.

EDIT :
So far what I have done is this :
Java Code:
```import java.util.Scanner;

public class f{
public static boolean isItInt(String inp)
{
char dgts[]={'0','1','2','3','4','5','6','7','8','9'};
int i=0,j=0,count=0;
for (i=0; i<inp.length(); i++)
{
for(j=0;j<dgts.length;j++)
if (inp.charAt(i)==dgts[j])
count++;
}
if (count==inp.length())
return true;
else
return false;
}

public static void main(String argv[]){
Scanner s = new Scanner(System.in);
String p=s.next();
System.out.println(p);
boolean x=isItInt(p);
System.out.println(x);
}
}```
But I am sure there is something easier than this, so let me know.
Last edited by QJack; 03-17-2010 at 03:30 PM.  Reply With Quote

2. ## Integer.parseInt("1234")  Reply With Quote

3. ## hi Originally Posted by QJack But I am sure there is something easier than this, so let me know.

in java when a number format convertion goes wrong then a exception is thrown. so try this peace of code

Java Code:
```public class ExceptionExample {

public static void main(String[] args) {
String str = "10000";
try {
System.out.println(Long.parseLong(str));
} catch (NumberFormatException nfe) {
System.out.println("NumberFormatException occured ");
nfe.printStackTrace();
}
}
}```
run the code with different str values to see what happens.  Reply With Quote

4. ## when you are accepting vis scanner use this method ...it will accept only integer.No need to have checking method for int.
nextInt()
hasNextInt()  Reply With Quote

5. ## Alright, thank u all! That was helpful.  Reply With Quote

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