Write a function called fare that computes the bus fare one must pay in a given city based on the distance travelled. Here is how the fare is calculated: the first mile is $2. Each additional mile up to a total trip distance of 10 miles is 25 cents.

function a = fare(dist,age)
x=round(dist);
if x>=0 && x<=1 
    fare=2;
    if x>1 && x<=10
        fare=2+(0.25*(x-1));
        if x>10
            fare=4.25+(0.1*(x-10));
        end
    end
end
if age<=18 || age>=60
    a=0.8*fare;
else
    a=fare;
end
end

[Sudarshan Agrawal]

i am getting the following error:- Undefined function or variable 'fare'.

Error in fare (line 15) a=fare;

Answer 1

[dpb]

function a = fare(dist,age) ... fare=2; ...

Unlike Fortran, the return value in a Matlab function is not stored in the function as a variable of the function name but one uses the defined return variable instead. You defined that as a in the function declaration.

I'd pick something a little more meaningful than just a, though, although that's not your problem.

a=2;

etc., will fix that reference issue. Maybe use

function cost = fare(dist,age)

or somesuch similar variable???

Is the distance actually rounded in the fare calculation or is it for any fraction of a mile over the previous full mile? The latter would seem more typical if not going to use actual mileage to nearest tenth or whatever...

[Stephen23]

Sudarshan Agrawal's "Answer" moved here:

I m still receiving the same problem. But the code is working for fare(0.2,67) only. the distance is rounded off to the nearest integer for the calculation

[dpb]

Yes, because when you used fare as a variable inside the function you aliased the function fare so it no longer is visible as a function; now it is a local variable.

As I said, "you can't do that!", Matlab is not Fortran.

But what are the expected answers for

   fare(1.2,67) 
   fare(1.7,67)

??

Answer 2

[Sudarshan Agrawal]

function cost = fare(dist,age)
x=round(dist);
if x>=0 && x<=1 
    f=2;
    if x>1 && x<=10
        f=2+(0.25*(x-1));
        if x>=11
            f=4.25+(0.1*(x-10));
        end
    end
end
if age<=18 || age>=60
    cost=0.8*f;
else
    cost=f;
end
end

The new code I tried!! It is working for fare(1.2,67) but not for fare(1.7,67).

[Walter Roberson]

After f = 2 you should be using elseif

 if x>=0 && x<=1
    f = 2;
 elseif x>1 && x<=10
   ...
 end

[Sudarshan Agrawal]

Thanks a lot!! Its working now. But why was the code not working when i used nested if statements??

[Walter Roberson]

With the structure you had, the test x>1&&x<=10 could only be made if x>=0&x<=1 had succeeded. The scope of the successful test if the first if extends until the matching "end" or "else" or "elseif"

[dpb]

And there'll still be a similar problem with the x>=11 portion

Answer 3

[Sarthak Shukrey]

my question doesnt demand for any 'if or else' statements , what will be the solution then ? TIA

[Walter Roberson]

Logical indexing?

Answer 4

[Nimra Mubeen]

function fare =taxi_fare(d,t)

fare=5+(ceil(d-1)*2)+(ceil(t)*.25)

[Gopichand Kunamaneni]

i could not understand this function. explain me in detail if possible. many thanks in advance

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/function.html

https://www.mathworks.com/help/matlab/ref/ceil.html

https://www.mathworks.com/help/matlab/matlab_prog/matlab-operators-and-special-characters.html#bvg3oy_-5