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

Problem :- Write A C++ Program To Find Sum Of The Following Series 1+2+3+4+5+6 . . . . . n .

Logic :- This is very simple series you just need to print sum of 1 to n terms ,there are two method you can use either use for loop or use formula Running time of using formula is Constant or
Running time of using for loop is O(n) in words ' Order of N '

Method 1:- sum of series from 1 to N.

Formula =n(n+1)/2

Method 2:- sum of series from 1 to N.

for(i=1;i<=n;++i)
{
sum+=i;
}
If you are interested then you can modified this series for large number or you can try below series .

Method 1:- 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()
{
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:-

Method 1:-

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#### post written by: Ghanendra Yadav

Hi, I’m Ghanendra Yadav, SEO Expert, Professional Blogger, Programmer, and UI Developer. Get a Solution of More Than 500+ Programming Problems, and Practice All Programs in C, C++, and Java Languages. Get a Competitive Website Solution also Ie. Hackerrank Solutions and Geeksforgeeks Solutions. If You Are Interested to Learn a C Programming Language and You Don't Have Experience in Any Programming, You Should Start with a C Programming Language, Read: List of Format Specifiers in C.