Question

Modify your program above that asks the user to enter number of cities he/she would like to enter population. Then ask the user to enter the population for each city and produce the bar graph

Here is an example of program’s output. User input is shown bold.

Please enter number of cities: 4

Enter the population of city 1 : 10000 Enter the population of city 2: 15000 Enter the population of city 3: 9000 Enter the population of city 4: 18000

POPULATION
(each * = 1000 people)

City 1 : **********
City 2 : *************** City 3 : *********
City 4 : ******************

Input validation: Do not accept population less than 0.

Here is an example of program’s output if user input is less than zero. (Error message is in Red. (Assume that user enter 3 for number of cities in this case)

Enter the population of city 1 : -20 Enter the population of city 2 : 3000 Enter the population of city 3 : 4000

Population can’t be negative. Please re-enter

Enter the population of city 1 : 2000 Enter the population of city 2 : 3000 Enter the population of city 3 : 4000

POPULATION
(each * = 1000 people)

City 1 : ** City 2 : *** City 3 : ****

Here is what I have below: ( I don't know how to display output as red text and I need to enter Population can’t be negative. Please re-enter (in red))

#include <iostream>

using namespace std;

int gcd(int a, int b)

{

if (a == 0)

return b;

return gcd(b % a, a);

}

int ngcd(int nums[], int n)

{

int result = nums[0];

for (int i = 1; i < n; i++)

result = gcd(nums[i], result);

return result;

}

int main()

{

int *dynamicArray;

int size;

do

  

{

cout<<"Enter the number of cities ( >0)::";

cin>>size;

}while(size<=0);

  

dynamicArray = new int[size];

  

for(int i=0;i<size;i++)

  

{

do

  

{

cout<<"Enter the population of City "<<i+1<<" (>0)::";

cin>>dynamicArray[i];

  

}while(dynamicArray[i]<=0);

  

}

  

cout<<endl<<"Bar plot of the cities ::"<<endl;

int unit=ngcd(dynamicArray,size);

cout<<"\tone * = "<<unit<<endl;

  

for(int i=0;i<size;i++)

{

cout<<"City "<<i+1<<" :: ";

  

for(int j=0;j< dynamicArray[i]/unit;j++)

  

{

cout<<"*";

}

  

cout<<endl;

  

}

  

return 0;

}

Answer 1

Here is your required code :-

#include<iostream>

using namespace std;

#define NUM_CITIES 4

int main(){

int population[NUM_CITIES], temp;                       // taking population

bool negEntered;

while(1){

negEntered =false;

for(int i=0; i<NUM_CITIES; i++){

cout<<"Enter the population of city "<<(i+1)<<": ";             //taking the population from the user

cin>>population[i];      // taking values

if(population[i]<0)

negEntered = true;                      // condition fot if user entered less than 0 or negative value

}

if(!negEntered)

break;

cout<<"Population can’t be negative. Please re-enter Enter the population of city"<<endl;

}

for(int i=0; i<NUM_CITIES; i++){

cout<<"City "<<(i+1)<<": ";

temp = population[i];

while(temp>0){

cout<<"*";

temp = temp - 1000;

}

cout<<endl;

}

return 0;

}

Output :-