A loop inside a loop

Question

I am using MATLAB for part of my final year project. I am solving a geometric series such as the sum of x^j, starting from j=0 up to n-1. I have the following code so far:

$Variable dictionary
%N Number of terms to sum
%alpha Sum of series
%x Vector of constants 
%n Loop counter

N = input('Enter the number of terms to sum: ');
alpha = 0;
x = [0.9 0.99 0.999 0.9999 0.99999 0.999999];
for n = 0:N-1
alpha = alpha + (x.^(n));
end
format long
alpha

I want to be able to put the value of n in myself and to be able to input more than value of n . Is it possible to do a loop inside a loop for this? For example declare N as a vector then use the for loop I currently have inside it?

Answer 1

This code would work with string input -

N = input('Enter the number of terms to sum: ');
N = str2num(N);

Rest of the code stays unchanged.

Enter input as a string, ie as an example -

Enter the number of terms to sum: '2 5 8 11 14 17'