G Question 5(10pt): Vector Vectors are similar to arrays, but they can grow dynamically in an efficient way. Write a program that asks the user to repeatedly enter positive integers and stop when the user enters -1.

I am using vectors for this program.

#include <iostream> //for input output functions

#include <vector> // constructs a vector

using namespace std; / identifies objects like cout cin

int main() // start of main() function body

{

vector<int> vec; // vector of integers

int input; // to store the input integer entered by user

while(input!=-1) {//loop continues until the user enters -1 to stop

cout<<"Enter positive integers: ";

cin>>input;  // reads the input from user

vec.push_back(input); } // enter integer elements into the vector

Explanation:

The size of the input integers is not known which means that how many positive integers to enter is not known so vectors are used here which work just like arrays but the difference is that the vectors can change their size.

The while loop continues to execute and user is prompted to enter integers until the user enters -1 to stop. When user types -1 the loop ends.

push_back() is a member function of vector class which is used to enter elements ( here the integer values) in the vector. Each new element is added at the end of the vector, which means every element is entered after the last element which was entered in the vector currently. This increases the size of the vector.

In order to see the integers stored in the vector, a loop is used with cout statement to display the contents on the output screen as follows:

for(int i=0;i<vec.size()-1;i++) {

/* loops through the vector to display its elements Here size-1 will display all elements before -1 is entered */

cout<<vec[i]<<" "; } //display the integers

The program along with the output is attached.