INR & DCR affect the flag register

Do the increment and decrement instructions affect the flag register in 8085 instruction set........

 

If I recall correctly, they affect all the flags but the carry flag. If you're programming in 8085 asm, you surely must have an instruction set reference.

 

My sir told that DCR affects the flag but INR doesn't affect the flag... is it so...

 

You are saying 'flag', but there is a whole set of flags. I recommend you read your materials, and have your sir do the same.