Question

I am trying to figure out how to properly execute a while loop and a do/while loop in the same program using java. I am stuck at just writing the while loop. I made a condition but I can't figure out how to get it to loop if the condition is true?? Also I have to write a do/while loop in the same program.

here are the details:

• This lab demonstrates the use of the While Loop and the Do While Loop as error checking mechanisms.
• You will be using each of these loops to solve the same problem.
• Please put them both in the same program.
• When you test the code, you will not see a difference in the way they execute - but there will be a difference in the logic when writing the code.
• You will want to write a refined algorithm for both to see the logic differences

Here is what I have written in JAVA so far:

import java.util.Scanner;

public class whileloopanddowhile //BEGIN Class Definition (must be same as file name)
{
public static void main (String[] args) //BEGIN Main Method
{
//Declare variables
int number;

//List all Class Objects here
Scanner scan = new Scanner(System.in);
  
//Executable Statement Section, user input
System.out.println ("Enter a grade from 0 to 100 ");
number = scan.nextInt();
  
//This is where the code goes
while (number < 0 && number > 100 )
{   
System.out.println ("ERROR! Must enter a grade between 0 and 100");
}

System.out.println ("You have enetered a valid grade");
  

}//END main method

}

Thank you for any help and clarification!

Answer 1

import java.util.Scanner;

public class Whileloopanddowhile {

    public static void main(String[] args) //BEGIN Main Method
    {
        //Declare variables
        int number;

        //List all Class Objects here
        Scanner scan = new Scanner(System.in);

        //Executable Statement Section, user input
        System.out.println("Enter a grade from 0 to 100 ");
        number = scan.nextInt();

        //This is where the code goes
        while (number < 0 || number > 100) {
            // Incorrect user input 
            System.out.println("ERROR! Must enter a grade between 0 and 100");
            
            // Get input from user again
            System.out.println("Enter a grade from 0 to 100 ");
            number = scan.nextInt();            
        }

        System.out.println("You have entered a valid grade");

        // do while loop
        do 
        {
            // Check if the grade is invalid
            if(number < 0 || number > 100)
               System.out.println("ERROR! Must enter a grade between 0 and 100");
            
            // Get input from user
            System.out.println("Enter a grade from 0 to 100 ");
            number = scan.nextInt();
        }
        while(number < 0 || number > 100);
        
        System.out.println("You have entered a valid grade");
        
    }//END main method
}



*************************************OUTPUT***************************************************


Enter a grade from 0 to 100 
-36
ERROR! Must enter a grade between 0 and 100
Enter a grade from 0 to 100 
150
ERROR! Must enter a grade between 0 and 100
Enter a grade from 0 to 100 
35
You have entered a valid grade
Enter a grade from 0 to 100 
-12
ERROR! Must enter a grade between 0 and 100
Enter a grade from 0 to 100 
150
ERROR! Must enter a grade between 0 and 100
Enter a grade from 0 to 100 
25
You have entered a valid grade