In a population the birth rate and death rate are calculated
In a population, the birth rate and death rate are calculated as follows:
Birth Rate = Number of Births ÷ Population
Death Rate = Number of Deaths ÷ Population
For example, in a population of 100,000 that has 8,000 births and 6,000 deaths per year, the birth rate and death rate are:
Birth Rate = 8,000 ÷ 100,000 = 0.08
Death Rate = 6,000 ÷ 100,000 = 0.06
Design a Population class that stores a population, number of births, and number of deaths for a period of time. Member functions should return the birth rate and death rate. Implement the class in a program. Input Validation: Do not accept population figures less than 1, or birth or death numbers less than 0. (C++)
Solution
#include<iostream>
 using namespace std;
class Population
 {
    long population;
    long no_births;
    long no_deaths;
 public:
    //constructor to initialize private members to zero
    Population()
    {
       population = 0;
        no_births = 0;
        no_deaths = 0;
    }
    //method to set values of an object of type Population
    void set_population(long pol, long births, long deaths)
    {
        population = pol;
        no_births = births;
        no_deaths = deaths;
    }
    //method to calculate birth rate
    double birth_rate()
    {
        double rate =((double)no_births/population)*100;
        return rate;
    }
    //method to calculate death rate
    double death_rate()
    {
        double rate = ((double)no_deaths/population)*100;
        return rate;
    }
};
int main()
 {
    //declare an object of type population
    Population obj;
    //local variable to store values entered from user
    long polulation,births,deaths;
   cout<\"Enter values for population, number of births , number of deaths\ \";
    cout<<\"Population = \";
    cin>>polulation;
   cout<<\"births = \";
    cin>>births;
   cout<<\"deaths = \";
    cin>>deaths;
   //set above values for an object pol
    obj.set_population(polulation,births,deaths);
   cout<<\"Birth rate = \"<<obj.birth_rate()<<\"%\"<<endl;
    cout<<\"Death rate = \"<<obj.death_rate()<<\"%\"<<endl;
   
 }
------------------------------------------------------------------------
output
Population = 200000
 births = 12344
 deaths = 8970
 Birth rate = 6.172%
 Death rate = 4.485%


