How to display rate within a given date range(in the question below) using map in cpp?

My question is:

Province/State,Country/Region,Lat,Long,1/22/20,1/23/20,1/24/20,1/25/20,1/26/20

,Afghanistan,33.0,65.0,0,0,0,0 
,Albania,41.1533,20.1683,0,0,0,0,0
,Algeria,28.0339,1.6596,0,0,0,0,0 
,Andorra,42.5063,1.5218,0,0,0,0,0 
,Angola,11.2027,17.8739,0,0,0,0,0 
New South Wales,Australia,33.8688,151.2093,10,0,20,0,0  
Northern Territory,Australia,-12.4634,130.8456,5,2,3,0,0  

The above is a csv file.I have to read the country, start date and end date from the user and print the rate values within that range?Also, I have to calculate the average of recovery rate per day in that country and print it. How can this be done? If start date entered by user is 01/22/2020 and end date is 1/24/2020 and country is Australia, Expected result should be like:

Date           Rate
01/22/2020      7.5(10+5/2)
01/23/2020      1((0+2)/2)
01/24/2020      11.5((20+3)/2)