Question

q1

Why would a programmer use files instead of keyboard and monitor screen? List three C++ statements required to access data in disk file (think of libraries statement, required objects, required function calls, how to read/write).

q.2

What is the task of the recursive function below and how is it achieving the task you have identified?

int strange(int n)
{
int result;
if (n == 1)
{
result = 0;
}
else
{
result = 1 + strange(n / 2);
}
return result;
}

Answer 1

With files we can use the large data efficiently.For people who can't enter the data for them it is useful.

The libraries we used are #include<fstream>

#include<fstream>

main()

{

  std::fstream f;
  f.open ("dmo.txt", std::fstream::in|std::fstream::out|std::fstream::app);
  f << " some text";//write into file

getline(cin,line) //read line from file

f.close()

}

2)

The function takes the value and it adds the value 1 to the result until the number becomes 0

suppose if value is 9

result =1+result(9/2)=1+result(4)

result(4)=1+result(2)

result(2)=1+result(1)

result(9)=1+1+1+result(1)=1+1+1+0=3

It gives the value of how many times it takes to reach 0