How Can i write a function that takes a structure array and returns this array with bubble sorting

I want to write a function that takes a structure array holding information about students(name,age,gpa etc.) and returns this array by ordering the students with respect to their age by bubble sort.

function  a=structarray (age,a)
for i=1:length(a)-1
  if a(i).(age)>a(i+1).(age)
    T=a(i);
    a(i)=a(i+1);
    a(i+1)=T;

i write this. but of course it is not working.pls guys help me.

[Walter Roberson]

What inputs would be typical for the age parameter ?

By the way:

a([i, i+1]) = a([i+1,i]);

exchanges without needing any temporary variable.

[Dart Min]

a(1).name='Matt';
a(1).age=22;
a(1).gpa=77;
a(2).name='Chris';
a(2).age=23;
a(2).gpa=45;
a(3).name='Park';
a(3).age=26;
a(3).gpa=81;
a(4).name='Stewie';
a(4).age=19;
a(4).gpa=44;

This is like my data and i want to use bubble sort to ordering respect to ages.

[Walter Roberson]

When you call the function, passing in that a as the second parameter, what would you pass in as the first parameter?

What difficulties are you observing with your code?

[Dart Min]

I can't call the function. I don't know what should i put in argument side. So i think the header section is wrong. when i write "function a=structarray(a)" is also not working.

Answer 1

[Walter Roberson]

function  a=structarray(a)
for i=1:length(a)-1
  if a(i).age > a(i+1).age
    T=a(i);
    a(i)=a(i+1);
    a(i+1)=T;
  end
end

[Dart Min]

Yeah but how can i call the function

[Walter Roberson]

a(1).name='Matt';
a(1).age=22;
a(1).gpa=77;
a(2).name='Chris';
a(2).age=23;
a(2).gpa=45;
a(3).name='Park';
a(3).age=26;
a(3).gpa=81;
a(4).name='Stewie';
a(4).age=19;
a(4).gpa=44;

sorted_a = structarray(a);

[Dart Min]

thanks a lot. but now only a(3) and a(4) changed. Then function stopped.

[Walter Roberson]

That is because your bubble sort algorithm needs more work.

You only make a single pass through the data. But suppose the least age was in the last entry. Your code would exchange that with the second last entry, but would not then proceed to "bubble" that lowest age from the second last entry all the way back to the first entry.

Answer 2

[Stijn Haenen]

Maybe this will work:

ages=[structurearray.age];
[a,b]=sort(ages);
newstructurearray=structurearray(b);

The used structure is attached.

[Walter Roberson]

sort() is not a bubble sort.

[Stijn Haenen]

Ah i missed that,

maybe this:

a(1).name='Matt';
a(1).age=22;
a(1).gpa=77;
a(2).name='Chris';
a(2).age=23;
a(2).gpa=45;
a(3).name='Park';
a(3).age=26;
a(3).gpa=81;
a(4).name='Stewie';
a(4).age=19;
a(4).gpa=44;
ages=[a.age];
[b]=unique(ages);
new_a=[];
for i=1:numel(b)
    num=(ages==b(i));
    new_a=[new_a;a(num)];
end

[Walter Roberson]

That just pushes the sorting off into unique() but the assignment requirement is to use bubble sort.