How to fix an error in my code?

Hello everyone!

I hope ypu all good and healty

I write this code on a script file and MATLAB shows me that there is a mistake in the fifth line

This is the code:

function operator1=add(op1,op2)

op1=input('Enter an number:');

op2=input('Enter an number:');

arith_operator=input('Enter an operator:','s');

if arith_operator== +

operator1=op1+op2;

fprintf('ans=%i',operator1)

else

disp('Error!,Try again!')

end

end

MATLAB shows me that the mistake is in this line:

if arith_operator== +

I try to fix it but I don't know how

Please,if anyone here knows how to fix it,let me know how as soon as possible

Thank you all,have a great day!

Answer 1

[Walter Roberson]

if strcmp(arith_operator, '+')

[Mayada Almousa]

I try it and when I run the code and choose + the condition dosen't work

Answer 2

[Torsten]

Works for me:

op1=input('Enter an number:');
 op2=input('Enter an number:');
 arith_operator=input('Enter an operator:','s');
     if arith_operator== '+'
         operator1=op1+op2;
         fprintf('ans=%i',operator1)
     else
         disp('Error!,Try again!')
     end

[Mayada Almousa]

but you didn't use any function,in my project I should use function:(

[Torsten]

operator1 = add();

function operator1=add()
op1=input('Enter an number:');
op2=input('Enter an number:');
arith_operator=input('Enter an operator:','s');
if arith_operator== '+'
    operator1=op1+op2;
    fprintf('ans=%i',operator1)
else
    operator1 = NaN;
    disp('Error!,Try again!')
end
end

[Walter Roberson]

Using == is going to lead to trouble if the user enters more than one character.

Answer 3

[Image Analyst]

This works fine. Put all this into one m-file:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
markerSize = 40;
result = add(1, 2);

function operator1 = add(op1, op2)
% Ignore incoming op1 and op2 and ask for new ones.
op1=input('Enter an integer:');
op2=input('Enter an integer:');
arith_operator=input('Enter an operator:','s');
if strcmp(arith_operator, '+')
    operator1 = op1 + op2;
    fprintf('\nThe result = %d.\n', operator1)
else
    message = sprintf('Error!\nYou need to enter a plus sign!\nTry replacing user and try again!');
    uiwait(warndlg(message))
end
end

[Mayada Almousa]

Thanks for your help but it desen't work

[Image Analyst]

Did you hit Enter after you typed +?

It definitely works. I just tried it again and it works.

Enter an integer:8

Enter an integer:9

Enter an operator:+

The result = 17.

>>

I'm attaching the actual m-file I used. Don't alter it -- just run it.