Nested while loop problem

Question

Aik Khim Tan 2016-3-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/275198-nested-while-loop-problem

回答： Walter Roberson 2016-3-24

Hi,

I have a test matrix [1 2 3; 4 5 6; 7 8 9] which I provide as input to a function called sandbox. The function is included below:

    function [matchFound] = sandbox(input)
    i=1; j=1; matchFound=[];
    while (i<=size(input,1)) && (isempty(matchFound))
        while (j<=size(input,2)) && (isempty(matchFound))
            if input(i,j)==5
                matchFound=1;
            end
            j=j+1;
        end
        i=i+1;
    end
    end

When I set i=1 in the second line the output is matchFound=[]; but when I set i=2 the output becomes matchFound=1. I have no clue why this happens. Could someone please help?

Best wishes