Q-04: Write a C/C++ program to compute the sum of the first n terms of the series.
S = 1 - 2 + 3 - 4 + 5 . . . n		 
    
Using - C

  
  

    
      #include<stdio.h>
      void main() {
        int n, i, sum=0;
        printf("Enter the number of terms: ");
        scanf("%d",&n);
        
        for(i=1; i<=n; i++){
            if(i%2==0)
              sum -= i;
            else
              sum += i;
          }
        
        printf("Sum of the Series: %d",sum);
        }

OUTPUT

Enter the number of terms: 7
Sum of the Series: 4

        
Using - C++

        
        

        
          #include<iostream>
using namespace std;
int main() {
int n, sum=0;
	cout<<"Enter the number of terms: ";
	cin>> n;
	
		for(int i=1; i<=n; i++){
			if(i%2==0)
				sum -= i;
			else
				sum += i;
		}	
		cout<<"Sum of the Series: "<< sum;
		
	return 0;
}

OUTPUT

Enter the number of terms: 4
Sum of the Series: -2