Are cost-benefit analysis and input-output analysis macroeconomics or microeconomics?

Both belong to microeconomics Although these analyses may be affected by macroeconomic factors, the choices they make do not have a significant impact on the overall economy of a country

Your teacher is right, cost-benefit analysis is a generalized economic concept that applies to both macroeconomics and microeconomics, so the question of whether it belongs to the macro or the micro depends entirely on the scope of the analysis. If it's a company's analysis, it's obviously micro, if it's an industry or an entire economy, it's obviously macro.