Java While Loop

Java While Loop. In this article, i will go through how to incorporate a While loop into our sample program using the while loop in Java.

There are 2 kinds of While Loop

• While() – This will check the initial condition inside the parentheses before  initiating the conditional statement.
• do{}While()- This will initiating the loop , and check the condition later after that.

To explain how to use DO While loop in Java , i will create a sample program , which enable the user to input a number from 0 to 9 to guess the Secret number.

Let Step into the Code below to incorporate Java While Loop into our sample program

In the sample code below, i will create 2 function . The first one is to check whether the User have input the value more than “i>10”. The second function is to print out a value to warn the User that they did not follow instruction and have input  the value out of  the threshold 0<i <10. I will skip exception handling in this sample,where if the user enter a text instead of an integer the system will return an error.

1. First let create a function call overwrittten() to check whether the user input more than  the given threshold.
2. The function will overwrite the User input value , and return the value
3. Second create a function which warn the User , that they have input a value more than the given threshold,This function will print out a message
4. Now lets go back to our main and import the Scanner Library then create a new scanner object called “inputScanner”
5. Create 2 variable , “i & checkpoint”. we will need the i to get the while loop moving
6. Start our while loop by setting the condition while (i>=0 && i< 10 )
7. Print out the message to ask the user to guess the number between 0 to 9
8. Assign the User input from the object scanner to the variable checkInput
9. Use the overwrittten(checkInput) function to check the User Input
10. Use the warnUser(checkInput) to output a message warning the user whether they have key in the value within the required threshold.
11. Now lets assign our secret number. Our secret number is 8.When the User input 8 ,it will break out of the while loop and display the message “You have enter the Correct number the secret number is 8”
12. Voila , we have made it again . Just created our very first While loop in Java

package oop2;

import java.util.Scanner;

public class secretnumber {

	public static void main(String[] args) {
		
		Scanner inputScan1 =new Scanner(System.in);
		
		
		int i =0;
		int checkInput;
		
		
		while (i>=0 && i< 10 ){
			
			
			System.out.println("Guess the Secret number from 0-9, ");
			checkInput=inputScan1.nextInt();
			i=overwrittten(checkInput);
			System.out.println("you have enter "+checkInput);
			warnUser(checkInput);
			
			
			
				
			}
			
			else if (i==8){
				
				break;
				
				
			}
				
						
	        		
		}
		
		
	      System.out.println("You have enter the Correct number the secret number is 8");
		 
		  
		  
		  inputScan1.close();	  
	}
	
	public static int overwrittten(int userInput){
		int overwritevalue=2;
		
		if( userInput>=10){
			
			//Overwrite the Value
			overwritevalue =0;
			
		                  }
		
		else{
			
			
			overwritevalue =userInput;
		}
		
		return overwritevalue;
	}
	public static void warnUser(int input){
		
		if(input >=10){
			
			System.out.println("Hey Follow Instruction 0 to 9 only");
		}
		
	}
	

}

 

 
Check out how to create constructor in Java here
Check out Java Library at Oracle here