Why won't MATLAB see the two strings that I am comparing as equal?

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Zach
Zach 2013-12-7
评论： sixwwwwww 2013-12-7
I am doing this as an assignment for my highschool MATLAB course. I cannot understand why MATLAB does not see my volume ('v') as equal to one of the volumes in my if structure. I even changed one of the if statements to use strcmp() instead of isequal(), to no avail. I run the script and enter the information, and no matter what I enter for the volume it outputs my 'else' code and gives me this error :
Choose a material(pine, oak, maple, yew, willow, mahogany, cypress, birch, or walnut) oak
Mass units to be used (kg, g, mg): kg
Mass units to be used (m^3, cm^3,mm^3, L, or mL): L
Inputted volume units are invalid.
Undefined function or variable 'p2'.
(I hope I entered the code correctly)
if true
% code
endmat = input('Choose a material(pine, oak, maple, yew, willow, mahogany, cypress, birch, or walnut) ','s');
%
%
% m = input('Mass units to be used (kg, g, mg): ','s');
% v = input('Mass units to be used (m^3, cm^3,mm^3, L, or mL): ','s');
%
% v = lower(v);
%
% % Process
% % densities in kg/m^3
% switch mat
% case 'pine'
% p = 500;
% case 'oak'
% p = 600;
% case 'maple'
% p = 750;
% case 'yew'
% p = 670;
% case 'willow'
% p = 450;
% case 'mahogany'
% p = 850;
% case 'cypress'
% p = 510;
% case 'birch'
% p = 670;
% case 'walnut'
% p = 700;
% otherwise
% disp('Either the material you entered is not in the database, or your query is misspelled.')
% end
%
% if isequal(m,'kg')
% p1 = p;
% elseif isequal(m,'g')
% p1 = p*10^3;
% elseif isequal(m,'mg')
% p1 = p*10^6;
% else
% disp('Inputted mass units are invalid.')
% end
%
%
% if strcmp(m,'m^3')
% p2 = p1;
% elseif isequal(m,'cm^3')
% p2 = p1*100^3;
% elseif isequal(m,'mm^3')
% p2 = p1*1000^3;
% elseif isequal(m,'l')
% p2 = p1*1000;
% elseif isequal(m,'ml')
% p2 = p1*10^6;
% else
% disp('Inputted volume units are invalid.')
% end
%
%
% % Output
% disp(sprintf('The density of %s is %d %s/%s.',mat,p2,m,v))

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采纳的回答

sixwwwwww
sixwwwwww 2013-12-7
replace
m with v
in your last if-else structure as follow:
if isequal(v,'m^3')
p2 = p1;
elseif isequal(v,'cm^3')
p2 = p1*100^3;
elseif isequal(v,'mm^3')
p2 = p1*1000^3;
elseif isequal(v,'l')
p2 = p1*1000;
elseif isequal(v,'ml')
p2 = p1*10^6;
else
disp('Input volume units are invalid.')
end
  2 个评论
Zach
Zach 2013-12-7
Well aren't I observant... XP Thanks for the help! I guess sometimes you just need an outside set of eyes!
sixwwwwww
sixwwwwww 2013-12-7
hahhahaha. sometimes it happens to everyone especially in programming. so don't worry at all and keep programming

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