IP-03.c

Problem Statement

IP-03.c

Write a program to compute the sum of the first n terms of the series using a function: S=1−2+3−4+5−6+…

Source Code

#include <stdio.h>

int sum_of_series(int);

int main()
{
    int n;
    printf("Enter the n: ");
    scanf("%d", &n);
    printf("\nSum of the first %d terms of the series = %d", n, sum_of_series(n));
    return 0;
}

int sum_of_series(int n)
{
    int sum = 0;
    int i;
    for (i = 1; i <= n; i++)
    {
        if (i % 2 == 0)
        {
            sum -= i;
        }
        else
        {
            sum += i;
        }
    }
    return sum;
}

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● Author - Amit Dutta · Updated - 03 Jan 2026