File handling in c++ please help

Question

You have a file “data.txt”. It contains integers. The very first number in the file tells you that how many total input cases are there in the file, the next number tells you that how many of the next numbers you have to add together. You will show the output on the screen and store it in a separate file “sum.txt”.
Sample input File:
2
2 4 5
3 6 5 4

Answer 1

Show your attempts.