Matlab function calling basic -

i'm new matlab , learning basic grammar.

i've written file getbin.m:

function res = getbin(num_bin, bin, val) if val >= bin(num_bin - 1)     res = num_bin; else     = (num_bin - 1) : 1         if val < bin(i)             res = i;         end     end end 

and call with:

num_bin = 5; bin = [48.4,96.8,145.2,193.6]; % bin stands intermediate borders, there 5 bins fea_val = getbin(num_bin,bin,fea(1,1)) % fea pre-defined 280x4096 matrix 

it returns error:

error in getbin (line 2) if val >= bin(num_bin - 1)  output argument "res" (and maybe others) not assigned during call "/users/mac/documents/matlab/getbin.m>getbin". 

could tell me what's wrong here? thanks.

you need ensure every possible path through code assigns value res.

in case, looks that's not case, because have loop:

for = (num_bins-1) : 1     ... end 

that loop never iterate (so never assign value res). need explicitly specify it's decrementing loop:

for = (num_bins-1) : -1 : 1     ... end 

for more info, see documentation on colon operator.