ploting 4 graphs for various constant values

Hello, i want to write code for function x=a*exp(b), where b=0:2*pi, 'a' is positive value entered by user. This should be four times, i mean 4 values of a entered by user so 4 graphs drawn on window.

clear all; close all;

for i=1:4

a=input('write positive a:', 's') b= 0:2*pi; x=a*exp(b); subplot(2,2,i),plot(x) end

However this code doesn't work well, i mean it draws completely the same for all values of a!! and more strangely when i write a=10 it gives me an error msg:

Error using * Inner matrix dimensions must agree. x=a*exp(b);

Answer 1

[Orion]

Hi,

you used input with a second argument 's', so a is interpreted as a string and not a number

for getting a string :

   a=input('write positive a:', 's')
   class(a)

for getting a number:

   a=input('write positive a:')
   class(a)

[Kentman]

Thanks for your answer Orion,it works quite fine now. But is it really necessary to write class(a)? what does it serve here? Because i tried input command without class and it serves quite well!

[Orion]

glad it works.

and i wrote the command

class(a)

just so you can see the class of the variable in the command window. It has no impact on the code and you don't need to keep it. It's just a useful function to know when you analyse datas.