Suppose we have a vector of integers declared as shown below

Suppose we have a vector of integers declared as shown below. For parts a-c of this problem, you are going to write some sections of code that will manipulate this vector.

vector <int> data;

Finish writing a section of code that will read integers from cin, until there are no more integers to read, and add the value which was read to the vector:

int input;

while ( cin >> input )

{

}

B). Write a call to the STL algorithm which will sort the vector. Do not write a sort function… just give the line or lines of code required to actually call the STL sort function:

C). List two of the three header files which will need to be included in order for all of the code in parts 3a and 3b to work:

D). Finish writing a recursive function called sum(), which will return the sum of the integers contained within the array passed to it (this has nothing to do with 3a-3c). Hint: if the size is 0, the function should return 0.

// Recursive function to sum an array

int sum( const int data[], int size )

{

}

Solution

// C++ code
/*
header files which will need to be included in order for all of the code in parts 3a and 3b to work
#include <vector> and
#include <algorithm> to sort vector
#include <fstream> to open file
*/

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

// Recursive function to sum an array
int sum( const int data[], int size )
{
    if(size == 0)
      return 0;
    else
      return data[size-1]+sum(data,size-1);
}

int main ()
{
// vector
vector <int> data;

// open file
ifstream inputFile (\"input.txt\");
if (inputFile.is_open())
{
    int input;
    while ( inputFile >> input )
    {
        data.push_back(input);
    }   
    inputFile.close();
}
else cout << \"Unable to open file\";

cout << \"Unsorted vector: \";
for (int i = 0; i < data.size(); ++i)
{
    cout << data[i] << \" \";
}
cout << endl;
cout << endl;

// call to the STL algorithm which will sort the vector
sort(data.begin(), data.end());

cout << \"Sorted vector: \";
for (int i = 0; i < data.size(); ++i)
{
    cout << data[i] << \" \";
}
cout << endl;
cout << endl;

int array[data.size()];
for (int i = 0; i < data.size(); ++i)
{
    array[i] = data[i];
}
int total = sum(array,data.size());
cout << \"Sum: \" << total << endl;

return 0;
}

/*
input.txt
7
8
5
4
3
6
8
9
1
10

output:
Unsorted vector: 7 8 5 4 3 6 8 9 1 10
Sorted vector: 1 3 4 5 6 7 8 8 9 10
Sum: 61

*/