MATLAB: How to plot a for loop

for looplooploopsMATLABplotplotting

Can someone tell me what's wrong with this code? It is only plotting at x=6 because the loop obviously ends there.
e=2.718;
for x=-2:1:6
    if x<-1
        y=e.^(x+1)
    elseif x>=-1 && x<5
        y=2+cos(pi.*x)
    elseif x>=5
        y=10.*(x-5)+1
    else
        fprintf('answer not given')
    end
end
x=-2:6;
plot(x,y)
Thanks you

Best Answer

You’re not subscripting either ‘x’ or ‘y’. That’s important because ‘x’ is negative and zero, so it can’t be used as indices. Also, the lengths of both vectors have to be the same.
A few tweaks and your code works:
e=2.718;
x=-2:1:6;
for k1 = 1:length(x)
      if x(k1)<-1
          y(k1)=e.^(x(k1)+1);
      elseif x(k1)>=-1 && x(k1)<5
          y(k1)=2+cos(pi.*x(k1));
      elseif x>=5
          y(k1)=10.*(x(k1)-5)+1;
      else
          fprintf('\nanswer not given\n')
          y(k1) = NaN;
      end
  end
  x=-2:6;
  plot(x,y)
Related Question