how to use if comparison

my problem is i want to compare like the code below and if the condition is met i want it to keep its current value but if the condition is not met iwant to change the value into 0 but when i run the code all the value turn to zero. Can you correct my code?

for c=2:length(fbtbopfin)
for d=1:length(fbtbopfin)
    if fbtbopfin(c,1)==fbtbopfin(d,2)   
    fbtbopfin(c,1)=fbtbopfin(c,1);
    else fbtbopfin(c,1)=0;
    end
    end
    end

here is the fbtbopfin matrix

1 2

2 3

3 4

4 5

5 6

6 7

7 8

0 0

10 11

11 12

12 13

13 14

15 16

16 17

17 18

2 19

19 20

20 21

21 22

3 23

23 24

24 25

6 26

26 27

27 28

29 30

30 31

31 32

9 15

12 22

18 33

25 29

Answer 1

[Walter Roberson]

The code is working properly according to the requirements that you stated. You want it to change the value to 0 if the condition is not not met, and it does exactly that.

Suppose that your first column V contains 5 and 3, length 2. You for c=2:2, for d=1:2. V(2) is 3, V(1) is 5, the two are not equal so you set V(2)=0. Then you go on to V(2) vs V(2) and you are comparing the newly written 0 to itself and those are equal so you leave that alone.

If you think about your code you will see that it will zero all entries except the first unless all of the entries are equal to each other.

[Walter Roberson]

My guess is that you want logic something like this:

found = false;
for index = lower : upper
    if something involving variable(index) is true
        found = true;
        break;
    end
    if ~found
        set something to 0
    end
end

[Enda Sembiring]

thanks for the response,sir. I'm still new with matlab is 'found' a function? because i cant find any example in mathwork about that, can you please explain more. Thank you beforehand.