Question

Write a program in C++ to read a number n and find out the sum of the integers from 1 to

then from 1 to 3, then 1 to 4, and so on and to display the sum of the integers from 1 to

n.

For example, from

1 to 2 = 1

1 to 3 = 3

1 to 4 = 6

1 to 5 = 10

1 to 6 = 18

Answer 1

#include <iostream>
using namespace std;
//Summ out 1 -2 1-3 and out to display 1-n
int main() {
  int n;
  cout<<"Please enter n: ";
  cin>>n;
  int sum=1;
  for(unsigned i=2;i<=n;i++)
    {
      cout<<1<<"-"<<i<<" ="<<sum<<endl;
      sum+=i;
    }
  return  0;
}