What is wrong with my Triangle Area Function Code

HI Folks,

I am just getting started so lease take it easy on me.

I am trying to write a function that will take in 1 ,2 or 3 arguments. I am naming it triangle_area and as you can guess for one input an equilateral triangle is assumed, for 2 a right angled triangle and if three inputs are given they are checked at either end to make sure the triangle inequality is met. If not an appropriate error should be generated and if all is well it goes on to find the area of the general triangle.

function [A] = trianglearea(a,b,c)
    if nargin ==1
A=a^2/sqrt(3)

elseif nargin==2
A =a*b/2
if c<=a-b
            error( 'Silly you, c is too small.')
end
if c>=a+b
                error( 'Silly you, c is too big.')
end

                      else  s = (a+b+c)/2;
          A = sqrt(s*(s-a)*(s-b)*(s-c));
      end

[Ronan Downes]

I probably need to check if any of the three triangle inequalities fail

if a+b>c; a+c>b or b+c>a

[Adam]

c doesn't exist when nargin == 2 so why are you doing checks on it there?

[Ronan Downes]

Thanks

I am getting closer

function [A] = triangle_area(a,b,c) if nargin ==1 A=a^2/sqrt(3)

elseif nargin==2 A =a*b/2 else

% b+c>a % error( 'Silly you, that triangle is impossible')

s = (a+b+c)/2;
      A = sqrt(s*(s-a)*(s-b)*(s-c))
  end

Just need to set up an alarm if too many arguments entered or if triangle inequality is broken

a>b+c b>a+c or c>a+b should all trigger alarms

Answer 1

[Ronan Downes]

function [A] = triangle_area(a,b,c) if nargin ==1 A=a^2/sqrt(3) elseif nargin==2 A =a*b/2 else % b+c>a % error( 'Silly you, that triangle is impossible') s = (a+b+c)/2; A = sqrt(s*(s-a)*(s-b)*(s-c)) end