Question

5.41 exercise Visual C#:How to Program (World Population Growth) World population has grown considerably over the centuries. Continued growth could eventually challenge the limits of breathable air, drinkable water, arable cropland and other limited resources. There's evidence that growth has been slowing in recent years and that world population could peak sometime this century, then start to decline. For this exercise, research world population growth issues online. Be sure to investigate various viewpoints. Get estimates for the current world population and its growth rate (the percentage by which it is likely to increase this year). Write a program that calculates world population growth each year for the next 75 years, using the simplifying assumption that the current growth rate will stay constant. When displaying the results, the first column should display the year from year 1 to year 75. The second column should display the anticipated world population at the end of that year. The third column should display the numerical increase in the world population that would occur that year. Using your result, determine the year in which the population would be double what it is today, if this year's growth rate were to persist. (Hint: Use double variables because int variables can store values only up to approximately two billion. Display the double values using the format F0, which displays the values rounded to the closest whole number - 0 means no digits to the right of the decimal point.)

Answer 1

C# Program:

using System;
                  
public class Program
{
   public static void Main()
   {
       Double startingPopulation, currentPopulation, growthRate, newPopulation, difference;
      
       //Reading Current population
       Console.Write("\n Enter Current Population: ");
       currentPopulation = Double.Parse(Console.ReadLine());
      
       //Assigning to Starting population
       startingPopulation = currentPopulation;
      
       //Reading Growth Rate
       Console.Write("\n Enter Population Growth Rate: ");
       growthRate = Double.Parse(Console.ReadLine());
      
       int doubleYear = 0;
      
       //Printing header
       Console.WriteLine("\n Year \t Anticipated Population \t Increase in Population \n");
      
       //Iterating for 75 years
       for(int i=1; i<=75; i++)
       {
           //Calculating new population
           newPopulation = currentPopulation + (currentPopulation * (growthRate / 100.0));
          
           //Calculating difference
           difference = newPopulation - currentPopulation;
          
           //Printing values
           Console.WriteLine(" {0:n0} \t\t\t {1:n0} \t\t\t {2:n0} ", i, newPopulation, difference);
      
           //Finding year in which population is doubled
           if(doubleYear == 0 && (newPopulation >= (2*startingPopulation)))
           {
               doubleYear = i;
           }
          
           //Updating population
           currentPopulation = newPopulation;
       }
      
       //Printing year in which population is doubled
       Console.WriteLine("\n Year in which population doubled is {0} \n", doubleYear);
   }
}

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Sample Output:

Enter Current Population: 5832560 Enter Population Growth Rate: 3.25 Year Anticipated Population Increase in Population 6, 022,118 6,217,837 6, 419, 917 6, 628, 564 6, 843,992 7,066, 422 7,296, 081 7,533,203 7,778,033 189,558 195, 719 202,080 208,647 215,428 222,430 229, 659 237,123 244, 829 10 8,030, 819 8,291,820 8,561, 304 8,839, 547 9,126, 832 9, 423,454 9, 729, 716 10,045, 932 10, 372,425 10,709, 529 11,057, 588 11,416, 960 11, 788,011 252, 786 261,002 269, 484 278,242 287,285 296, 622 306, 262 316,216 326, 493 337,104 348,060 359,372 371,051 20 33, 869,792 34, 970, 561 36,107,104 37,280,585 38, 492,204 39,743,200 41,034, 854 42,368,487 43, 745, 463 45,167,190 46, 635,124 48,150, 766 49,715, 665 51,331,425 52,999, 696 54, 722,186 56, 500, 657 58,336,928 60, 232,879 62,190,447 64,211, 637 1,066,119 1,100, 768 1,136, 543 1,173,481 1,211, 619 1,250,997 1,291, 654 1,333, 633 1,376, 976 1,421,728 1,467,934 1,515, 642 1,564,900 1. 615,759 1,668,271 1,722,490 1, 778, 471 1,836,271 1,895, 950 1,957,569 2,021,190 56 60 61 62 63 64 65 69 Year in which population doubled is 22