combine Input with formula

Question

Karel 2012-7-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/44595-combine-input-with-formula

I have written the folowing function:

function [ sort1 , sort2 ] = front(x,N)
      Y1=input('frontière inférieure: ','s') ;
      s1=eval(Y1);
      Y2=input('frontière supérieure: ','s');
      s2=eval(Y2);
      [Non important part of the function]
end

The idea is that the user can input either a number, or an expression (example given : y2 = (x^2-36) and y1=0

However, when I run the program, I get the folowing error:

frontière inférieure: 0
frontière supérieure: (36-x^2)
    ??? Error using ==> mpower
    Inputs must be a scalar and a square matrix.
    Error in ==> front at 6
        s2=eval(Y2);
    Error in ==> principal_1 at 18
[y1,y2]=front(xtab,n);