Question

Checker for integer string

Forms often allow a user to enter an integer. Write a program that takes in a string representing an integer as input, and outputs yes if every character is a digit 0-9.

Ex: If the input is:

1995

the output is:

yes

Ex: If the input is:

42,000

or

1995!

the output is:

no

Hint: Use a loop and the Character.isDigit() function.

import java.util.Scanner;

public class LabProgram {
public static void main(String[] args) {
Scanner scnr = new Scanner(System.in);
String userString;
// Add more variables as needed

userString = scnr.next();
/* Type your code here. */
}
}

Answer 1

Output:

Code:

import java.util.Scanner;

public class LabProgram {
    public static void main(String[] args) {
        Scanner scnr = new Scanner(System.in);
        String userString;
        int flag = 1;
      
        userString = scnr.next();
        //traverse each character of the string
        for(char ch : userString.toCharArray()){
            //check if current Character is digit or not
            if(!Character.isDigit(ch)){
                flag=0; //set flag to zero to indicate invalid string
                break;
            }
        }
        //check if there are only digits
        if(flag==0){
            System.out.println("no");
        } else{
            System.out.println("yes");
        }
    }
}