Receiving error when trying to obtain multiple inputs

I have three user inputs with three prompts before hand. I am trying to have the code ask a question, user inputs, assigns string input to a variable, and have that do it three times (once for each prompt). Although after entering a value for the first prompt, the code returns an issue with the second prompt. I am not sure what the issue is. Can someone help me out?

I have included the entire code, I am aware that the "if" statements are reptitive and could be optimized.

Below is the code for reference:

%Assuming using Glass FRP rated at 480 Mpa (Range: 480-1600 Mpa)

%Defining Variables (in MPA): 
plastic_tensile = 23.00001401;
frp_tensile = 479.9999027;


%Recieve user inputs for material chosen, atmospheric pressure, and radius of opening:
prompt1 = ("Please enter the material you would like to test (a. plastic b. frp): ");
prompt2 = ("Input the atmospheric pressure you would like to test (in PSI): ");
prompt3 = ("Input the radius of the opening you would like to calculate (in meters): ");

picked_mat = input(prompt1, 's');
psi = input(prompt2, 's');
r = input(prompt3, 's');

pimatlwr = lower(picked_mat);

%Calculate response based on info
% F = P*A
%oparea meaning (Area of Opening)

if pimatlwr {"plastic"}
    oparea = (pi * (r^2));
    newtons = (psi * oparea);
    nm2 = (newtons/oparea);
    mpaarea = (nm2/1000000);
    dataset1 = [mpaarea];
    reply1 = ("The area of the opening would exert %2.0f on the sheet. The sheet can only withstand 23 MPA, thus it would break.");
    reply2 = ("The area of the opening would exert %2.0f on the sheet. The sheet can withstand 23 MPA, thus it would not break.");
    if mpaarea > plastic_tensile 
        text = fprintf(reply1, dataset1);
    elseif mpaarea < plastic_tensile 
        text2 = fpritnf(reply2, dataset1);
    end
end 

if pimatlwr {"frp"} 
    oparea = (pi * (r^2));
    newtons = (psi * oparea);
    nm2 = (newtons/oparea);
    mpaarea2 = (nm2/1000000);
    dataset2 = [mpaarea];
    reply1_1 = ("The area of the opening would exert %2.0f on the sheet. The sheet can only withstand 480 MPA, thus it would break.");
    reply2_1 = ("The area of the opening would exert %2.0f on the sheet. The sheet can withstand 480 MPA, thus it would not break.");
    if mpaarea > frp_tensile 
        text1_1 = fprintf(reply1_1, dataset2);
    elseif mpaarea < plastic_tensile 
        text2_1 = fpritnf(reply2_1, dataset2);
    end
end

Answer 1

[Voss]

It's a good idea to share the complete error message you received, including the line number and the text of the line the error happened (all of which is reported to you in the error message itself).

Anyways, here's how you can fix some of the potential errors I see:

picked_mat = input(prompt1, 's');
% don't use 's' in input() with prompt2 and prompt3, since
% you want to store numeric values in psi and r:
psi = input(prompt2);
r = input(prompt3); 

% ...

% this is not valid syntax:
% if pimatlwr {"plastic"}

% I imagine you mean:
if strcmp(pimatlwr,"plastic")
    % ...
end

% then similarly for pimatlwr {"frp"} later on
if strcmp(pimatlwr,"frp")
    % ...
end

% Or maybe you want to allow the user to type "plastic" or "a" to select
% plastic, etc.:
if strcmp(pimatlwr,"plastic") || strcmp(pimatlwr,"a")
    % ...
end

% And watch out for "fpritnf" typos:

% text2 = fpritnf(reply2, dataset1);
text2 = fprintf(reply2, dataset1);

% text2_1 = fpritnf(reply2_1, dataset2);
text2_1 = fprintf(reply2_1, dataset2);

And I guess mpaarea in the second if block should be mpaarea2, but it's not clear that they can't both be mpaarea (depends on what other code not seen is doing). Just use the right name within a block.

[smguzman]

Hello,

Thank you very much for your response, I appreciate the detailed feedback, it was more than I was expecting. This is all the code I have thus far, and it most likely won't extend farther than this. I will make the corrective changes here and follow-up with anything else if needed.

[Voss]

You're welcome! Let me know if you have more questions.