Nested while loop not working properly

Hello guys,

I have a problem with nested while loops. The following code was supposed to give me term0=2 on the first iteration but it keeps giving me the value '8'.

From what I understand, this nested loop is supposed to do 'i=1' and then iterate k from 1 to 8, then end 'k' loop, do i+1 and k=1 and then start all over.

What am I missing here?

Thank you!!

    i = 1;
    j = 1;
    k = 1;  
    S1= 0;
    S2= 0;
    
          
    while i <= 7
        k=1; 
        S1=0;
             while k <= 8       
        S1 = S1 + abs(V(k))*(real(Y(i+1,k))*cos(angle(V(i+1))-angle(V(k)))+imag(Y(i+1,k))*sin(angle(V(i+1))-angle(V(k))));               
        k = k+1;        
             end
        term0=i+1;
        term1=P(i+1);
        term2=(abs(V(i+1))*S1);
        deltaP(i) = term1-term2; 
        i= i+1;
    end

[David Fletcher]

I suspect it is doing exactly what is asked. You are not saving the values of term0 etc. so they will be overwritten on each iteration of the i loop. The value of 8 for term0 reflects the final value of term0 on the last iteration of the i loop (i=7+1 is 8)

[flowguy]

Yeah.... so obvious :)

I added the indice (i) to the term0, term1 and term2 to see the iterations properly.

Thanks David!

Answer 1

[Shivani Dixit]

Your code is working fine as of assigning value to 'term0' (as expected), you are not able to view the value of 'term0'=2 because of reassignment at every iteration. The following example can illustrate how to analyse the above situation.

We can have two ways to resolve the above issue:

1. Using indexing of the variable 'term0', so that there is a proper understanding of what is going on inside the nested loop. Basically when we are not indexing 'term0' , what is happening is, the values assigned to 'term0' changes after every iteration , so what we have at last is the final vale of 'term0' that is 8. The following code illlustrates this :

  i = 1;
    j = 1;
    k = 1;  
    S1= 0;
    S2= 0;
    % added index for term0 as idx_0
    idx_0=1;
          
    while i <= 7
        k=1; 
        S1=0;
             while k <= 8       
        %S1 = S1 + abs(V(k))*(real(Y(i+1,k))*cos(angle(V(i+1))-angle(V(k)))+imag(Y(i+1,k))*sin(angle(V(i+1))-angle(V(k))));               
        k = k+1;        
             end
        term0(idx_0)=i+1;
        idx_0=idx_0 +1;
        %term1=P(i+1);
        %term2=(abs(V(i+1))*S1);
        %deltaP(i) = term1-term2; 
        i= i+1;
    end
>> term0

term0 =

     2     3     4     5     6     7     8

2. Another simple way could be just removing semicolon (;) after 'term0' so that when the code is executed all the values assigned to 'term0' after every iteration is displayed.