I was emphaised during my theory exams that the leading note must go to tonic,but when i start studying comtemporary music I found out that most composers compositions leading note sometimes goes to tonic.When i check this my my theory teacher he said this could me mode scales/jazz chords.I need your opinion.Thank you

It could also be a case of having to know the rules before you can break them....

well thats more classical stuff, leading note to tonic, in jazz we tend to not follow those rules, our chords are like major 7ths and all that. well modal scales, i dnt know what your saying there but i think he means that in Cmajor Dorian or whatever even though you think its a 7th, its not a 7th in the key of c major, if im answering your question right, jazz uses alot of modal scales, specially in improvisation so i can see where your teachers coming from.

But for theory just keep to doing the Leading note to tonic i reckon Specially intests where they ask you to write a melody down. Its easier to do leading note to tonic then leading note to 3rd, well in songs in minor keys the 7th is raised so it is dissonant, but in major i think its ok, still not preferred though.

Even in Baroque and Classical music It depends on how you arrive at the leading note whether or not it "wants to" go to the tonic. And even when it does you don't have to go there directly. The resolution can be delayed, interrupted, diverted, just so long as it happens eventually.

That was very insightful. Sometimes when "idling away" on the piano, I touch a leading note but drag it out with lots of additional notes before going to the tonic. I never realised it until you mentioned it. Thank you~