C++ Program To Find Sum Of The Following Series 1+2+3+4+5+6 . . . . . n

 Using Formula

#include<iostream>
using namespace std;

int main()
{
 int i,n,sum=0;

 cout<<"\n1+2+3+4+5+6+……+n\n";
 cout<<"\nEnter The Value Of N:\n";
 cin>>n;

 sum=(n*(n+1))/2;
 
 cout<<"\nSum = "<<sum<<endl;
 return 0;
}

Output:

1+2+3+4+5.....+n

Enter the value of n:

10

sum=55

Using For Loop

#include<iostream>
using namespace std;

int main()
{
 int i,n,sum=0;

 cout<<"\n1+2+3+4+5+6+……+n\n";
 cout<<"\nEnter The Value Of N:\n";
 cin>>n;

 for(i=1;i<=n;++i)
 {
  sum+=i;
 }
 cout<<"\nSum = "<<sum<<endl;
 return 0;
}

Method 2:- Using Formula

#include<iostream>
using namespace std;

int main()
{
 //By-Ghanendra Yadav
 int i,n,sum=0;

 cout<<"\n1+2+3+4+5+6+……+n\n";
 cout<<"\nEnter The Value Of N:\n";
 cin>>n;

 sum=(n*(n+1))/2;
 
 cout<<"\nSum = "<<sum<<endl;
 return 0;
}

Output:

1+2+3+4+5.....+n

Enter the value of n:

10

sum=55