while loop with questdlg box

Hello, I would like to know is it possible to make such a program with while loop and questdlg box, that would calculate sum of variable e.g. 'F' in each new .msi file selection:

Here is my code:

P=1;
while P>0

s=uigetfile('.msi');

a=importdata(s,' ',5);
c=[a.data]; 
c(1,:)=[];
c(361,:)=[];
g=getfield(a, 'textdata');

F = cellfun(@(g) str2double(g(11:end)),g(2,1));
DBD = cellfun(@(g) str2double(g(6:end-3)),g(3,1));

choice=questdlg('one more?','take or not', 'default');

switch choice
    case 'Yes'
        P=1;
    case 'No'
        P=0;
    case 'cancel'
        P=0;
end
end

Please suggest your ideas :)

[Walter Roberson]

for P>0 would not be valid syntax. Perhaps you meant "while" instead of "for" ?

[Tomas]

Yes, You are right, but problem still exisist.

[Jan]

The problem is not clear. If you add "P = 1" before the loop, the program should work. But what do you want to sum and what problems occur?

[Tomas]

Yes, You are right, I forgot to add P=1.

The program should ask user for .msi file to open, then get a name of file that is needed to import, after that pick 'F' value and all rest. So I want to do this multiple times and calculate all of those .msi files 'F' values in one.

[Tomas]

Solved, ty for all your time :)