How to find sum of several integers input by user using do/while, While statement or For statement

Question

Please help out here. I want to create a program whereby a user inputs several numbers (let's say 6 numbers from his/ her head). The program should then go ahead and calculate the sum of all these numbers. I however have to use a loop statement, either For statement, While statement or do/while statement. This is what I have so far:

#include <iostream>

using namespace std;

int main()
{
    int count = 1;
    int sum = 0;
    int number;
    int numberitems;

    cout << "Enter number of items: \n";
    cin >> numberitems;

    cout << "Enter number: \n";
    cin >> number;

    do {

        sum = sum + number;

        count++;
    } while (count <= 6);
}

AND HERE IS THE OTHER CODE USING WHILE STATEMENT

#include <iostream>

using namespace std;

int main()
{
    int count = 1;
    int sum = 0;
    int number;

    cout << "Enter number: \n";
    cin >> number;

    while (count <= 6) {
        sum = sum += number;

        count++;
    }
    cout << sum << endl;
}

I know this is beginner stuff, well am a beginner so help out a sister politely. THANKS

Answer 1

The FOR loop worked well, I modified it a tiny bit:

#include<iostream>
using namespace std;
int main ()
{

    int sum = 0;
    int number;
    int numberitems;


    cout << "Enter number of items: \n";
    cin >> numberitems;

    for(int i=0;i<numberitems;i++)
    {
        cout << "Enter number: \n";
        cin >> number; 

        sum=sum+number;

    }
    cout<<"sum is: "<< sum<<endl;
}

HOWEVER, the WHILE loop has got some errors on line 11 (Count was not declared in this scope). What could be the issue? Also, if you would have a solution using DO,WHILE loop it would be wonderful. Thanks

Answer 2

You should do:

#include<iostream>
using namespace std;
int main ()
{

    int sum = 0;
    int number;
    int numberitems;


    cout << "Enter number of items: \n";
    cin >> numberitems;

    for(int i=0;i<numberitems;i++)
    {
        cout << "Enter number <<i<<":" \n";
        cin >> number; sum+=number;
    }
    cout<<"sum is: "<< sum<<endl;
}

And with a while statement

#include <iostream>
using namespace std;
int main ()
{
    int sum = 0;
    int number;
    int numberitems;
    cin>>numberitems;

    cout << "Enter number: \n";

    while (count <=numberitems)
    {
        cin >> number;
        sum+=number;
    }
    cout << sum << endl;
}

Answer 3

Do note that if you're adding stuff, you might always want to check that you're not going beyond the limits of int (especially in homework exercises). Also, int main () should return an int.

Using a "do .. while" loop:

#include<iostream>
using namespace std; 
int main () 
{

  int sum = 0;
  int previous = 0;
  int number;
  int numberitems;
  int count = 0;

  cout << "Enter number of items: ";
  cin >> numberitems;

  if ( numberitems <= 0 ) 
  {
    //no request to perform sum
    cout << "Quitting without summing.\n\n";
    return 0;
  }

  do
  {
    cout << "Enter number to add : ";
    cin >> number; 

    sum+=number;

    // check here that the addition didn't break anything.
    // Negative + negative should stay negative, positive + postive should stay positive
    if ((number > 0 && previous > 0 && sum < 0) || (number < 0 && previous < 0 && sum > 0))
    {
      cout << "Error: Beyond int limits !!";
      return 1;
    }

    count++;
    previous = sum;

  }
  while ( count < numberitems);

  cout<<"sum is: "<< sum<<endl;

  return 0;
} 

Answer 4

#include<iostream>
int main()
{//initialize variables
    int limit;
    int num;
    int sum=0;
    int counter=0;

    cout<<"Enter limit of numbers you wish to see"<<" ";
    cin>>limit;
    cout<<endl;

while(counter<limit)
{

   cout<<"Enter number "<<endl;
  cin>>num;

  sum=sum+num;
  counter++;
}
cout<<"The sum of numbers is "<<" "<<endl

return 0;
}

Answer 5

A simple program shows how to use for loop to find sum of serveral integers.

#include <iostream>    
using namespace std;

int main ()
{
    int sum = 0;

    int endnum = 2;

    for(int i = 0; i<=endnum; i++){
        sum += i;
    }
    cout<<sum;
}