Question

Write a series of codes using WHILE loops C++

1. Ask the user for a number and adds even numbers for 1 to the user entered number.

2. Write another piece of code that asks the user for 2 numbers and adds up the numbers between and including the numbers.

3. Write another piece of code that asks user for a file name and then add up all the numbers for the file.

Answer 1

First Code:

#include<bits/stdc++.h>

using namespace std;

int main()

{

    int t;

    cout<<"Enter the no: \n";

    cin>>t;

   int j=1;int sum=0;

    while(j<=t)

    {  

        if(j%2==0)

            sum++;

            j++;

   }   

    cout<<sum<<"\n";    

    return 0;

}

Second Code :

#include<bits/stdc++.h>

using namespace std;

int main()

{

    int x,y;

    cout<<"Enter the first number: ";

    cin>>x;

    cout<<"Enter the second number: ";

    cin>>y;

   int sum=0;

    while(x<=y)

    {  

            sum=sum+x;

            x++;

    }   

    cout<<sum<<"\n";    

    return 0;

}

Third Code:

#include <fstream>

#include <iostream>

#include <sstream>

using namespace std;

int main()

{

   ifstream fin;

    char filename[20];

cout<<"Enter The File Name With Extension\n";

cin>>filename;

fin.open(filename);

if (!fin)

   {

    cout<< "File  not found." << endl;

    return -1;

   }

   string line;

    getline(fin, line);

    istringstream str(line);

    int sum = 0, next = 0;

    while (str >> next)

sum += next;

   fin.close();

   cout<<sum<<"\n";

  return 0;

}