Program in matlab to add the digits of a number

Problem

Write a program in matlab to add the digits of the given number using functions. For example if the input is 523 then the program should give the output as 5 + 2 + 3 = 10

Solution

This program in very simple and easy to understand. To understand this program, you will have to know few concepts. First of all look at the program and if you don't understand, go to explanation section under the program section, and if you still don't understand the program then head on to the links given below and read the concept so that you will understand the program easily. The links are as follows:
1) Function in matlab
2) num2str function in matlab
3) length function in matlab
4) for loop in matlab
5) str2num function in matlab
6) string referencing in matlab
7) vectors in matlab

Program

function res = add_digits(n)
%this function will add all the digits of th given number.
%for example if the number is 523 then the output of the program will be
% 10 = 5 + 2 + 3

%First of all we will convert the number to a string 
%so that we can reference each digit in the number easily
strin = num2str(n);

%Now we will create a sum variable to store the sum of the digits
sum = 0;

%A for loop to iterate through the digits
for i = 1:length(strin)
    sum = sum + str2num(strin(i));
end

res = sum;

to download the above program in matlab file format,then click here: add_digits.m

Explanation

Here in the function first we have written the comment so that if for any future usage, if you type the help command with the corresponding function name then you should get to know what the program is. And in the program it has been clearly explained what the program is, and I think it is not necessary here again to discuss the same thing.
Here we have used the num2str function with the input number so that we can reference the digits in the numbers like the vectors in Matlab.
In the next statement we have initiated a sum variable so that as soon as we find out the digit in the for loop we will simply add the number to the sum and finally at the end of the loop we will get the result.
Now digging deep we will find the for loop, we can get to understand this example using the number 523 and going iteration by iteration.

First iteration

The value of the sum is 0 and the value of i is , now the sum value gets added to the number 5 (the string we will reference will again be converted back to number using the str2num function). Finally at the end of the first iteration we will get the values as follows:

sum = 5, i = 1

Second iteration

The same explanation goes here as for the first iteration. But we will just see the values :

sum = 5+2 = 7, i = 2

Third iteration

Values are as follows:

sum = 7+3 = 10, i = 3

By this iteration the digits in the number are over and the loop comes to halt. Finally to return the output we will by referencing the res variable to the sum variable which has the value of the sum.

The above program has been high lighted using hilite.me

i have tried to explain this post so that it will be easy to understand for everyone. If you have any doubt or problem in understanding or anything, please do contact me so that it will not only help you but will also help others. you can contact me here: contact me

Also comment your solution for a given input in the comment below.

Keywords: add digits, matlab function, number