Write a recursive function to obtain the running sum of first 25 natural numbers

PG74.c

#include <stdio.h>

int sum(int);

int main()
{
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    printf("\nSum of first %d number is: %d\n", num, sum(num));
    return 0;
}

int sum(n) int n;
{
    return (n == 1) ? 1 : n + sum(n - 1);
}