# Bubble sort for loop

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Matpar on 3 Oct 2019
Commented: Guillaume on 4 Oct 2019
Hi can a professional guide me in terms of a bubble sort using 2 for loops please!
I have been googling to help myself but it's challenging to understand how they actually work! I have no code!
Thanx in advance for assisting me and responding to my questions!

Ajay Kumar on 3 Oct 2019
Edited: Ajay Kumar on 3 Oct 2019
First try to understand the sorting algorithm. There are many videos on youtube that explains bubble sort.
num = numel(x);
for j = 0 : num-1
for i = 1: num-j-1
if x(i)>x(i+1)
temp = x(i);
x(i) = x(i+1);
x(i+1) = temp;
end
end
end

Matpar on 4 Oct 2019
forgive me I tired and well I am still here trying I manage to get the understnding going via the manaual way!
This is where i've gotten;
%% Exhaustive Search Implementation
%Imaginative Points Specified on the X Y plane of 2 dimensional Image
% Point W,X,Y,Z, the distance between W & Y as well as Z & W
w=[4,9]; %
x=[1,5]; %
y=[7,2]; %
z=[3,5]; %
wy=[11,3];
zw=[4,1];
%% Specified the distance of each point utilising the Euclidean Distance
%euclideanDistance = sqrt((w2-w1)^2+(x2-x1)^2+(y2-y1)^2+(z2-z1)^2);
%w>x>y>z>xz>wy
ed_wxyz = sqrt((9-4)^2+(5-1)^2 +(2-7)^2+(5-3)^2+(3-11)^2+(1-4)^2);
%% Specified Each Point Individually For Cross Validation Purposes
edw_x = sqrt((9-4)^2+(5-1)^2);
edx_y = sqrt((5-1)^2+(2-7)^2);
edy_z = sqrt((2-7)^2+(5-3)^2);
edz_w = sqrt((5-3)^2+(9-4)^2);
edx_z = sqrt((5-1)^2+(5-3)^2);
edw_y = sqrt((9-4)^2+(2-7)^2);
%% Created Variable T to Sort All Point In Descending Order
t = [edw_x,edx_y,edy_z,edz_w,edx_z,edw_y,ed_wxyz];
sortpoints = sort(t,'descend');
%% Display All Point Individually
disp('The Euclidean Distance of the points are=>');
disp('edw_x'); disp(edw_x);
disp('edx_y'); disp(edx_y);
disp('edy_z'); disp(edy_z);
disp('edz_w'); disp(edz_w);
disp('edx_z'); disp(edx_z);
disp('edw_y'); disp(edw_y);
disp('edw_x'); disp(ed_wxyz);
disp('Here are the points in **RANDOM** order');
%% Display Sorted Points In Descending Order From Matlab Built-in Sort Fucntion
disp(t);
disp('Here are the points in **DESCENDING** order');
%%
% *************************************************************************************
disp(sortpoints);
%%
% *************************************************************************************
disp('This point (X_Z) is the lowest calculation=> 4.4721')
Rik on 4 Oct 2019
This code has nothing to do with your question. The sort function doesn't use bubble sort, because there are much more efficient algorithms for sorting.
Guillaume on 4 Oct 2019
Indeed what has that code to do with the initial question?
Note that in each of the proposed code it would be more efficient to stop as soon as the inner loop has done a pass without any swapping, rather than continue scanning the whole array.
"I was of the opinion that the for loop was the solution"
There's not much difference between a for loop and a while loop. That was my point to Kumar. You can always rewrite a for loop as a while loop and vice-versa
for i = 1:10
%do something
end
is equivalent to:
i = 1;
while i <= 10
%do something
i = i+1;
end
while:
while somecondition
%do something
end
is equivalent to
for i = 1:Inf
if somecondition
break;
end
%do something
end