Thread: need help for cheking if input is digit ?

Hi every one so basically i'd like to know which method i can use so that the program checks if the input value is a digit or else outputs a message saying that `the value entered is not a number please retry later`
please i need an answer ASAP :/
thank u in advance

but mine is not a character its a whole string and it is required that i'm not using loops :/

can i have an example of that with a if statement exception ?? and here is my code i want an exception for my year and my day number so that the program outputs an error message if the input is other than a number

import java.util.Scanner; // Import Scanner class
public class DayOfYear
{


public static void main(String[] args)
{

final int JAN = 31;
final int FEB;
final int MAR = 31;
final int APR = 30;
final int MAY = 31;
final int JUN = 30;
final int JUL = 31; //Set final values for each month of the year
final int AUG = 31;
final int SEP = 30;
final int OCT = 31;
final int NOV = 30;
final int DEC = 31;


Scanner kb = new Scanner(System.in);

System.out.print("Enter a year: "); //prompt user to input a year value
int year = kb.nextInt();


boolean isLeapYear = true; // set value of the variable to true



if ( year <=1582 ) //first exception: year must be more or equal to 152

{
System.out.println("Error: year value must be a positive integer beyond 1582" + "\n");
}

else if ( ( year % 4 == 0 )&&( year % 100 != 0) || ( year % 400 == 0) ) // if conditions are true then year is a leap year

{
isLeapYear = true ;
}

else //else it's not a leap year

{
isLeapYear = false;
}



System.out.print("Enter a day number in that year: "); //prompt user to enter a day number
int dayNumber = kb.nextInt();

if ( (isLeapYear == true) && (( dayNumber > 366) || ( dayNumber < 0)) ) // if it's a leap year and daynumber higher than 366 or negative, ERROR

{
System.out.print("Error: day number value must be a positive integer more than 0" +
"\n" +" and less or equal to 366 (given that " + year + " is a leap year)" + "\n");
}

else if ( (isLeapYear == false) && (( dayNumber > 365) || ( dayNumber < 0)) ) // if it's not a leap year and daynumber higher than 365 or negative, ERROR

{
System.out.print("Error: day number value must be a positive integer more than 0" +
"\n" +" and less or equal to 365 (given that " + year + " is not a leap year)" + "\n");
}


}
}

Sorry for bothering you it is my first time using this forum :p but thank you for your help rally appreciate it

 
import java.util.Scanner;				// Import Scanner clas
public class DayOfYear
{
 
 
	public static void main(String[] args)
	{
 
				final int JAN = 31;
				final int FEB;
				final int MAR = 31;
				final int APR = 30;
				final int MAY = 31;
				final int JUN = 30;
				final int JUL = 31;							//Set final values for each month of the year
				final int AUG = 31;
				final int SEP = 30;
				final int OCT = 31;
				final int NOV = 30;
				final int DEC = 31;
 
 
		Scanner kb = new Scanner(System.in);
 
		System.out.print("Enter a year: ");				//prompt user to input a year value		
		int year = kb.nextInt();			
 
 
		boolean isLeapYear = true;				// set value of the variable to true 
 
 
 
		if ( year <=1582 )				//first exception: year must be more or equal to 1582
 
				{
					System.out.println("Error: year value must be a positive integer beyond 1582" + "\n");
				}
 
		else if ( ( year % 4 == 0 )&&( year % 100 != 0) || ( year % 400 == 0) )			// if conditions are true then year is a leap year
 
				{
					isLeapYear = true ;
				}
 
		else									//else it's not a leap year
 
				{
					isLeapYear = false;
				}
 
 
 
			System.out.print("Enter a day number in that year: ");		//prompt user to enter a day number
			int dayNumber = kb.nextInt();
 
		if ( (isLeapYear == true) && (( dayNumber > 366) || ( dayNumber < 0)) )			// if it's a leap year and daynumber higher than 366 or negative, ERROR
 
			{
				System.out.print("Error: day number value must be a positive integer more than 0" +
								 "\n" +" and less or equal to 366 (given that " +	year + " is a leap year)" + "\n");
			}
 
			else if ( (isLeapYear == false) && (( dayNumber > 365) || ( dayNumber < 0)) )	// if it's not a leap year and daynumber higher than 365 or negative, ERROR		
 
						{
							System.out.print("Error: day number value must be a positive integer more than 0" +
											 "\n" +" and less or equal to 365 (given that " +	year + " is not a leap year)" + "\n");
			}
 
 
	}
}

I have a suggestion there is the .hasNextInt method but i don't really know how to use it. may i have some help please ??

Thank u very much you have been really helpfull i figured out where my error was, basically i needed an System.exit() thats why i wasn't having the error message
Here is my code maybe it will help someone else

Scanner kb = new Scanner(System.in);
 
		System.out.print("Enter a year: ");				//prompt user to input a year value
 
		boolean inputValidationYear;
 
		if	(!kb.hasNextInt())
				{
					inputValidationYear = false;
					System.out.println("Error: the year value you entered must be an integer");
					System.exit(0);
				}
 
		else{		inputValidationYear = true;	}
 
		int year = kb.nextInt();

Thanks again Norm