Write a program in c to:
a) calculate sn=1+1.2+1.2.3+…+1.2.3…n , n> 0

// Program in C to calculate sum of 1+1.2++1.2.3...n

// include header

#include <stdio.h>

// main function

int main()

{

   // variable Declaration and initialization

   int n,a,prod=1,sum=0;

   // ask to enter the value of n

   printf("enter the value of n:");

   // read the value of n

   scanf("%d",&n);

   for(a=1;a<=n;a++)

   {

       // calculate product

       prod=prod*a;

       // calculate sum of the series

       sum=sum+prod;

   }

   // print the sum

   printf("sum of the series is:%d",sum);

   return 0;

}

Explanation:

Read the value of n from user.initialize variables "prod=1" and

"sum=0".Iterate over a for loop to calculate product term as "prod=prod*a".Here prod will have product of all till "a-1" for each "a".Then "a" is multiplied with "prod" and then add to sum.After the loop ends, "sum" will have the total of all the terms.

Output:

enter the value of n:5

sum of the series is:153