WAP to compute the sum of the first n terms of the following series S =1-2+3-4+5…………….

---

#include<iostream.h>

#include<conio.h>

class summation

{

int  sum;

public:

void  s();

};

void  summation::s()

{

sum=0;

int n;

cout<<"enter the number of terms whose sum you want in the series"<<endl;

cin>>n;

                for(int i=1;i<=n;i++)

       {

       if(i%2!=0)

                sum=sum+i;

                else

                sum=sum-i;

       }

cout<<"the sum is :"<<sum;

}

void main()

{

clrscr();

summation obj;

obj.s();

getch();

}

---

Output:-