CODEWITHSUNDEEP
c#
Sajo Nezic
Sajo Nezic

Reputation: 51

Problem with the task. Write a program that determines and prints those numbers that are divisible by 3 among the entered numbers

I have a problem with the task. Firstly here are some guidelines for the task. Input of program: A natural number is loaded from the standard input first n and then n natural numbers each in a new line. Output of program:All loaded numbers divisible by 3 are printed in order on the standard output. Print each number in a separate line. Example I entered the numbers:

100    
99    
3    
4    
6

Each number must be in new line.

When I press enter the program must show me which numbers are divisible by 3. Example:

99    
3    
6

Here is my code

string a;
int n;
while (true)
{
    a = Console.ReadLine();
    if (a == string.Empty)
        break;

    n = Convert.ToInt32(a);
    {
        if (n % 3 == 0)
            Console.WriteLine(n);
    }
}

Problem is that when I enter a number that is divisible by 3 the program prints it immediately instead of waiting for me to finish entering numbers and only then to print numbers that are divisible by 3.

Upvotes: 2

Views: 151

Answers (2)

spzvtbg
spzvtbg

Reputation: 1024

Show bellow maybe you can find something usefull:

    static void Main()
    {
        var output = string.Empty;

        if (int.TryParse(Console.ReadLine(), out int iterations))
        {
            while (iterations-- > 0) // or iterations > 0 and if number pass then increase the iterations
            {
                if (int.TryParse(Console.ReadLine(), out int number) /*&& number != 0*/ && number % 3 == 0)
                {
                    output += $"{Environment.NewLine}{number}";
                    // iterations--;
                }
            }
        }

        Console.WriteLine(output);
    }

for the people they say string should not be added:

    static void Main()
    {
        var output = new StringBuilder(Environment.NewLine);

        if (int.TryParse(Console.ReadLine(), out int iterations))
        {
            while (iterations-- > 0) // or iterations > 0 and if number pass then increase the iterations
            {
                if (int.TryParse(Console.ReadLine(), out int number) /*&& number != 0*/ && number % 3 == 0)
                {
                    output.AppendLine($"{Environment.NewLine}{number}");
                    //iterations--;
                }
            }

            Console.WriteLine(output);
        }
    }

and solution with list:

    static void Main()
    {
        if (int.TryParse(Console.ReadLine(), out int iterations))
        {
            //var output = new List<int>();
            var length = iterations;
            var output = new int[length];

            while (iterations > 0) // or iterations > 0 and if number pass then increase the iterations
            {
                if (int.TryParse(Console.ReadLine(), out int number) /*&& number != 0*/ && number % 3 == 0)
                {
                    //outpu.Add(number);
                    output[length - iterations] = number;
                    iterations--;
                }
            }

            Console.WriteLine(string.Join(Environment.NewLine, output));
        }
    }

Upvotes: 3

Patrick Artner
Patrick Artner

Reputation: 51653

You need to restucture your program to first take all inputs and then process them.

You can do it like this:

using System;
using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        // storage for all numbers
        var numbers = new List<int>();

        while (true)
        {
            var a = Console.ReadLine();
            if (a == string.Empty)
                break;

            // error handling to avoid crashing if non integers are given
            try
            {
                // adding all numbers in case you want to do other things with them 
                numbers.Add(Convert.ToInt32(a));
            }
            catch
            {
                Console.WriteLine($"Not a number: {a}");
            }
        }

        // process the collected numbers
        foreach (var n in numbers)
        {
            if (n % 3 == 0)
                Console.WriteLine(n);
        }
    }
}

Testrun:

2
5
6
99
Apple
Not a number: Apple
102

6
99
102

As suggested in the comments: this will not fullfill the task given, you would need to read one number, then read as many inputs (so no while true: ... ).

Upvotes: 2

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