How to keep decimal value when getting data from a text file? - c++

Question

I have a text file with info like this (there are 127 lines, I'll provide a few too keep it short):
Gibraltar 133.25
Israel 104.81
Seychelles 85.89
United-Arab-Emirates 63.95
Falkland-Islands 49.73
My program does work in printing country name and number with the most vaccinations, however it just prints a whole number with no decimals. This is especially problematic with lowest since theres multiple countries with numbers between 0 and 1, and it just prints the first 0 down the list, so not the true minimum, here is my code:
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;
void file(string country[], double vaccinations[]);
void highest(string country[], double vaccinations[]);
void lowest(string country[], double vaccinations[]);
void average (string country[], double vaccinations[]);
void welcomeMessage();
int main() {
//declare variables and arrays, set vaccinations and countries arrays to 127 for the number of countries, amd subsequent vaccination data
string countries[127];
double vaccinations[127];
file(countries, vaccinations);
//call wecome message function
welcomeMessage();
//calls function to count highest vaccination rate and country names
highest(countries, vaccinations);
cout << endl;
//calls function to count lowest vaccination rate and country name
lowest(countries, vaccinations);
//calls function to print the average vaccination rate
//average(countries, vaccinations);
}
void welcomeMessage() {
cout << "Welcome to the vaccine data analysis program!" << endl;
cout << endl;
cout << "This program will print which country currently has admistered the most COVID-19 vaccine doses per 100 people" << endl;
cout << endl;
cout << "The program will also print which country currently has administered the least, per 100 people, as well as the average dose administration per 100 people, out of 127 countries on the list." << endl;
cout << endl;
}
void file(string country[], double vaccinations[]) {
int index = 0;
ifstream inFile;
inFile.open("vaccinations.txt");
if (!inFile.is_open()) {
cout << "Unable to open file." << endl;
} else {
while (index < 127) {
//add code to isolate country string
inFile >> country[index];
//add code to isolate vaccination percentage
inFile >> vaccinations[index];
index++;
}
}
}
void highest(string country[], double vaccinations[]) {
string highestCountry = country[0];
int highestTotal = vaccinations[0];
for (int i = 1; i < 127; i++) {
if (vaccinations[i] > highestTotal) {
highestTotal = vaccinations[i];
highestCountry = country[i];
}
}
cout << highestCountry << " has the highest number of vaccinations at " << fixed << setprecision(100) << highestTotal << " per 100 people." << endl;
}
void lowest(string country[], double vaccinations[]) {
string lowestCountry = country[0];
int lowestTotal = vaccinations[0];
for (int i = 1; i < 127; i++) {
if (vaccinations[i] < lowestTotal) {
lowestTotal = vaccinations[i];
lowestCountry = country[i];
}
}
cout << lowestCountry << " has the lowest number of vaccinations at " << fixed << setprecision(100)<< lowestTotal << " per 100 people." << endl;
}

Answer 1

You declared
int highestTotal = vaccinations[0];
therefore, it drops decimals when you copy floating point values into it.
Declaring highestTotal and lowestTotal as doubles should help:
double highestTotal = vaccinations[0];
and
double lowestTotal = vaccinations[0];
EDIT: as #Casey suggests, we can slightly rewrite it (you can add the welcome message and file correctness check if you wish);
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
struct Country {
string name;
double rate;
};
istream& operator>>(std::istream& in, Country& country) {
return in >> country.name >> country.rate;
}
int main()
{
ifstream inFile;
inFile.open("vaccinations.txt");
auto comparator = [](const Country& x, const Country& y) { return x.rate < y.rate; };
auto [min, max] = minmax_element(istream_iterator<Country>{inFile}, istream_iterator<Country>{}, comparator);
string highestCountry = max->name;
double highestTotal = max->rate;
cout << highestCountry << " has the highest number of vaccinations at " << highestTotal << " per 100 people." << endl << endl;
string lowestCountry = min->name;
double lowestTotal = min->rate;
cout << lowestCountry << " has the lowest number of vaccinations at " << lowestTotal << " per 100 people." << endl;
}