CODEWITHSUNDEEP
matlabif-statementlogical-operators
SimpleProgrammer
SimpleProgrammer

Reputation: 259

if, elseif, else statement will not execute correctly

I am currently working on a piece of code and the if, elseif, else statements will not cooperate with me. It is very simple code, most are just constants I've defined:

K1 = 0.174532925;
K2 = 0.20943951;

y0 = [0.0 15.2161 0.0 0.0];

ieout = [];

if isempty(ieout)
    if y0(1)>K1
        ieout = [ieout 5];
    elseif  K1>y0(1)>-K1 && y0(2)<0
        ieout = [ieout 1];
    elseif -K1>y0(1)>-K2 && y0(2)<0
        ieout = [ieout 2];
    elseif -K1>y0(1)>-K2 && y0(2)>0
        ieout = [ieout 3];
    elseif K1>y0(1)>-K1 && y0(2)>0
        ieout = [ieout 4];
    end
end

Now, my vector y0 have all zeroz except at the second position which is positive, so this means the last elseif statement should be executed. This is not the case, instead the statement before the last is executed and my vector ieout gets a scalar element 3 instead of 4.

This confuses me, why is this happening?

Upvotes: 0

Views: 50

Answers (1)

L. Scott Johnson
L. Scott Johnson

Reputation: 4382

You can't chain logical operators like 1<y<2. You have to use 1<y && y<2 So: 

K1 = 0.174532925;
K2 = 0.20943951;

y0 = [0.0 15.2161 0.0 0.0];

ieout = [];

if isempty(ieout)
    if y0(1)>K1
        ieout = [ieout 5];
    elseif  K1>y0(1) && y0(1)>-K1 && y0(2)<0
        ieout = [ieout 1];
    elseif -K1>y0(1) && y0(1)>-K2 && y0(2)<0
        ieout = [ieout 2];
    elseif -K1>y0(1) && y0(1)>-K2 && y0(2)>0
        ieout = [ieout 3];
    elseif K1>y0(1) && y0(1)>-K1 && y0(2)>0
        ieout = [ieout 4];
    end
end

Upvotes: 2

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