Answer:
Here is the C++ program:
#include<iostream> // to use input output functions
using namespace std; //to identify objects like cin cout
int main() { // start of the main() function body
// holds the value for starting number of organisms and number of days
int start_size, days;
/* stores value of daily population increase. The data type is set to double to take value of population increase as a fraction */
double pop_increase;
//prompts user to enter starting no of organisms
cout << "Enter the starting number of organisms: ";
cin >> start_size; //reads the value of starting number of organism
/* if the user enters start size value less than 2 this loop keeps executing until the user enters a value of start_size greater than or equal to 2*/
while(start_size < 2){
//displays message for the user to enter a start_size greater or equal to 2
cout<<"The starting number of organisms must be at least 2"<<endl;
cout << "Enter a number greater than or equal to 2: ";
cin >> start_size; } //reads the value of start_size entered by user
//prompts user to enter value for avg daily population increase
cout << "\nEnter average daily population increase as percentage: ";
cin >> pop_increase; //reads the value of population increase
/* if the user enters pop_increase value less than 0 this loop keeps executing until the user enters a positive value of pop_increase */
while(pop_increase < 0){
//prompts user to enter the valid positive value for population increase
cout<<"The average daily population increase must be a positive value"<<endl;
cout << "Please enter a positive value for population increase: ";
cin >> pop_increase; } //reads the value of pop_increase from user
cout << "\nEnter the number of days: "; //prompts to enter number of days
cin >> days;//reads the value of days input by user
/* if the user enters days value less than 1 this loop keeps executing until the user enters a value of days greater than or equal to 1*/
while(days < 1){
//prompts user to enter a valid value for number of days
cout<<"The number of days must be at least 1"<<endl;
cout << "Please enter a number of days greater than or equal to 1: ";
cin >> days; } //reads days input from user
//prints the message below
cout<<"\nSize of population for each day is given below";
cout << "\nDay\t\tPopulation"<<endl;
//prints the Day and Population separated by tab spaces
for(int i = 1; i <= days; i++){ //loop displays size of population for each day
start_size = start_size * (1 + pop_increase / 100.0);
//calculates size of population of organisms
//displays the values of i and start_size
cout << i << "\t\t" << start_size << endl; } }
Explanation:
the loop variable i starts from 1 and this loop body stops to execute when the value of i exceeds the value of number of days. The loop body has a statement start_size = start_size * (1 + pop_increase / 100.0); that computes the size of a population of organisms. The starting number of organism is multiplied by ( 1 + the increase in population) and this increase in population is divided by 100 to be expressed as a fraction. At the end, the result of this whole equation is stored in start_size variable. The last print statement prints the values of i and values of start_size computed by the above formula.
The screenshot of the program along with its output is attached.
