How to get the value (number) that is in a string?

To lighten my question ,for exemple let's take d='1'; I want to increment 1 it to get 2 as result. So I tried to convert it to double by using double(d)+1; I got 50. Obviously '1' is 49 in double , same thing I got by using int8 . which function should I use to get 2 as result?

Answer 1

[Image Analyst]

Like this:

doubleD = str2double(d);

[Zineb EL MORCHID]

Thank so much Savior .