for the example, if we have this data in file.csv
`> vacation, tourist, year
japan, 777899, 2018 switzerland, 839398, 2020 japan, 789999, 2020 london, 83939, 2017 london, 98383, 2014 russia, 645534, 2018 `
then, when we prompt = vacation; it will display all vacation list and show it frequency
display : japan : 2 switzerland : 1 london : 2 russia : 1
how can we do this in c programming lang?
