Calculate sum 1 + 2 + 3 +. . . .+n

 C++ Program to calculate the sum of a series up to N terms.This program calculates the sum of the series 1 + 2 + 3 +. . . . . . . . .+n and prints the result on the compiler screen. The last number n is input by the user. Sum of this series is calculated by the formula : sum=(n*(n+1))/2. For loop is used to print the whole series upto n and the sum is printed on compiler screen.

Source Code:-

#include<iostream.h>
#include<conio.h>
void main()
{
 int n,i;
 int sum=0;
 clrscr();
 cout<<"Program to calculatesum 1+2+3+...n by-Tarun Rawat\n";
 cout<<"\nEnter the value of n : ";
 cin>>n;
 sum=(n*(n+1))/2;
 cout<<"\nSum of the series: ";
 for(i=1;i<=n;i++)
 {
  if (i!=n)
  {
    cout<<i<<" + ";
  }
  else
  {
    cout<<i<<" =  "<<sum;
  }
 }
 getch();
}