Question

This program is for kindergartners to practice knowledge on numbers divisible by 5.

Write a code using a while loop, which keeps asking the user to enter an number divisible by 5. The program(i.e the while loop) terminates when the user enters a number divisible by 5, but keeps running if the user fails to enter a number divisible by 5. Also print appropriate message after each failed try. When successful, tell the user how many attempts were needed for success.

Answer 1

The program will ask the user to input numbers till the input number is divisible by 5. The program will show a message after each invalid input. After a succesful input, the number of attempts will be also printed by the program. Since the program has to be implemented using while loop, the first input should be normal, and the remaining inputs(if any) should go through iteration using while loop.

The algorithm of the program would be:

Step 1: Ask the first number from the user normally.

Step 2: In case of invalid number, show an error message.

Step 3: Start a while loop which will check if the first number is divisible by 5 or not. If the number is not divisible by 5, start a loop that will ask the user for a valid number.

Step 4: After each input, increase the count which should be initialized to zero. This will track the number of attempts.

Step 5: Lastly print the valid number and number of attempts when the program exits from the loop due to valid input.

The required program in C language is given below:

#include<stdio.h>       //import basic package

int main()               //main method
{
   int n,count=0;
  
   //code for first input
   printf("Enter a number divisible by 5 : ");
   scanf("%d",&n);       //requesting the user for a number
   count++;           //counting number of attempts
   if(n%5!=0)           //error message in case of invalid input
       printf("\nPlease enter a number which is divisible by 5.\n\n");
      
   //code for remaining inputs(if any) using while loop
   while(n%5!=0)       //the loop executes till valid input is given
   {
       printf("Enter a number divisible by 5 : ");
       scanf("%d",&n);       //requesting the user for a number
       count++;           //counting number of attempts
       if(n%5!=0)           //error message in case of invalid input
           printf("\nPlease enter a number which is divisible by 5.\n\n");
   }
  
   printf("\n................................\n");
   printf("Entered valid number: %d\n",n);       //printing the valid input
   printf("Number of attempts: %d",count);       //printing the number of attempts
   return 0;
}

Screenshot of the code:

Output:

NOTE: Since the language is not mentioned, the solution is given in some other languages below.

The required program in C++ is given below:

#include<iostream>       //import basic package
using namespace std;

int main()               //main method
{
   int n,count=0;
  
   //code for first input
   cout<<"Enter a number divisible by 5 : ";
   cin>>n;       //requesting the user for a number
   count++;           //counting number of attempts
   if(n%5!=0)           //error message in case of invalid input
       cout<<"\nPlease enter a number which is divisible by 5.\n\n";
      
   //code for remaining inputs(if any) using while loop
   while(n%5!=0)       //the loop executes till valid input is given
   {
       cout<<"Enter a number divisible by 5 : ";
       cin>>n;       //requesting the user for a number
       count++;           //counting number of attempts
       if(n%5!=0)           //error message in case of invalid input
           cout<<"\nPlease enter a number which is divisible by 5.\n\n";
   }
  
   cout<<"\n................................\n";
   cout<<"Entered valid number: "<<n;       //printing the valid input
   cout<<"\nNumber of attempts: "<<count;       //printing the number of attempts
   return 0;
}

Screenshot of the code:

Output:

The required solution in JAVA is given below:

import java.util.*;         //import basic package

public class Main           //defining a class
{
   public static void main(String[] args)      //main method
   {
        int n,count=0;
        Scanner sc=new Scanner(System.in);
      
        //code for first input
        System.out.printf("Enter a number divisible by 5 : ");
        n=sc.nextInt();       //requesting the user for a number
        count++;           //counting number of attempts
        if(n%5!=0)           //error message in case of invalid input
            System.out.println("\nPlease enter a number which is divisible by 5.\n\n");
      
        //code for remaining inputs(if any) using while loop
        while(n%5!=0)       //the loop executes till valid input is given
        {
            System.out.printf("Enter a number divisible by 5 : ");
            n=sc.nextInt();       //requesting the user for a number
            count++;           //counting number of attempts
            if(n%5!=0)           //error message in case of invalid input
                System.out.printf("\nPlease enter a number which is divisible by 5.\n\n");
        }
  
        System.out.println("\n................................\n");
        System.out.println("Entered valid number: "+n);       //printing the valid input
        System.out.println("Number of attempts: "+count);       //printing the number of attempts
   }
}

Screenshot of the code:

Output: