Why do I get an error?
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Hi I was writing a script for a program that ask the user to enter the material of an object and the surface's material to use the friction consent to find the force, and here is my script :
object=input('Enter the matiral of the object : ','s');
surface=input('Enter the matiral of the surface : ','s');
W=input('Enter weight : ');
U=[0.2 0.4 0; 0 0.35 0 ; 0 0 0.7];
%calculation_section
if object=='metal'
OB=1;
elseif object=='wood'
OB=2;
elseif object =='rubber'
OB=3;
elseif surface=='metal'
S=1;
elseif surface=='wood'
S=2;
elseif surface=='concrete'
S=3;
end
F=U(OB,S);
%output_section
disp(['The force is :',num2str(F)]);
The error i receive comes from different lines sometimes from this line OB=1; and sometimes from this line F=U(OB,S) each time I hit run it gives me a different error massage. I am stuck in this error for two days, I searched a lot but I couldn't fix it.I hope if you guys can help me.
2 个评论
David Fletcher
2018-3-10
you should note that object=='metal' will not return a logical scaler: instead it returns a 1x5 logical vector correspnding to a match (or not) in each of the character positions. If the things you are testing are of a different lengths then you will get an error. Use a string comparison function instead
Geoff Hayes
2018-3-10
采纳的回答
Jan
2018-3-10
Instead of a bunch of if statements with strcmp, you can use switch also:
switch object
case 'metal'
OB = 1;
case 'wood'
OB = 2;
case 'rubber'
OB = 3;
otherwise
error('Unexpected object.')
end
switch surface
case 'metal'
S = 1;
case 'wood'
S = 2;
case 'concrete'
S = 3;
otherwise
error('Unexpected surface.')
end
In addition you need two different if or switch blocks. In your case after an object was found, the surface is not examined anymore.
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