Question

Algorithm that finds the sum of numbers from 1 to N (including N) for the entered number N write step by step.  

Answer 1

1st Method: In this method, we take a variable 'SUM' assigned to '0' initially and another variable 'i' that varies from 1 to N for each loop, we use variable 'SUM' to stores the sum of value i.e., at some number Nth loop SUM(N) = SUM(N-1)+i. So, present value of sum is previous value of SUM + i. By the end of the loop we have SUM = 1+2+3+....+(N-1)+N.

Algoritham:

1) Take integer variables i, N, SUM.

2) Read the value N, which is number of terms in the the summation series.

3) Assign value of SUM to '0' i.e., SUM = 0;

4) START loop with variable i that varies from 1 to N.

5) Replace the value of SUM with previous SUM + K i.e., SUM = SUM + K.

6) End the loop.

7) Print the value of the SUM.

8) END.

2nd Method: In this method we use formula, we know that sum of first N (including N) Natural numbers is N(N+1)/2. we can use this formula to find the sum of numbers directly, with out using any loop.

Algoritham:

1) Take integer variables N, SUM.

2) Read the value N from the user, which is number of terms in the summation series.

3) Comupte value of SUM = N*(N+1)/2.

4) Print the value of SUM.

5) End.